Visible indicators for cold chain monitoring

Abstract

In a cold-chain ecosystem, one or more sensors capable of changing a color characteristic responsive to an altered temperature is described. The sensor is attached to a package such that, during shipment of the package, the altered temperature can cause the color characteristic of the sensor to change. A color state of the sensor following the altered temperature is analyzed.

Description

PCT Patent Application Attorney Docket No. 57274-0010WO1 VISIBLE INDICATORS FOR COLD CHAIN MONITORING CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application is a PCT application that claims priority to U.S. Provisional Patent Application No.63 / 559,741, filed on February 29, 2024; U.S. Provisional Patent Application No. 63 / 653,308, filed on May 30, 2024; and U.S. Provisional Patent Application No. No.63 / 662,848, filed on June 21, 2024; and each application is incorporated by reference in its entirety. BACKGROUND

[0002] Worldwide, a vast portion of the produced food fails to reach the consumer and is thrown away uneaten, being wasted. The discarded food causes a significant environmental and humanitarian burden. Food waste occurs along the entire supply chain spectrum – from its point of origin (e.g., a farm), to a processing production facility, to logistics distribution, to retailers, and to the consumer. Reasons for food waste include losses due to mold, pests, or inadequate climate control. Current food safety monitoring solutions provide limited accuracy and sensitivity, presenting false positive and negative events.PCT Patent Application Attorney Docket No. 57274-0010WO1 SUMMARY

[0003] The present disclosure describes visible indicators for cold chain monitoring.

[0004] In an implementation, a solution-based temperature detection device, comprising: a saline pocket; a saline solution contained within the saline pocket; and a textured surface contained within the saline pocket.

[0005] In an implementation, a method for temperature detection, comprises: providing a sensor capable of changing a color characteristic responsive to an altered temperature; attaching the sensor to a package such that, during shipment of the package, the altered temperature can cause the color characteristic of the sensor to change; and analyzing a color state of the sensor following the altered temperature.

[0006] In an implementation, a temperature detection device, comprises: at least one hydrochromic paint; a volume of ice; and a surface in contact with the volume of ice and painted with the at least one hydrochromic paint.

[0007] In an implementation, a temperature detection device, comprises: a volume of ice; and a power of hydrogen (pH) sensitive or enzyme sensitive indicator, wherein the pH sensitive indicator detects a pH of a thawed volume of ice.

[0008] In an implementation, a temperature detection device, comprising: a volume of solution; and an enzyme sensitive indicator, wherein the enzyme sensitive indicator detects an enzymatic reaction that occurs when the solution freezes.

[0009] In an implementation, a temperature detection device, comprises: an open grating structure; and a volume of refractive index-matching-solution frozen to the open grating structure rendering the open grating structure invisible.

[0010] In an implementation, a temperature detection device, comprises: an open grating structure or a Denisyuk hologram comprised of meltable or water-soluble material.

[0011] In an implementation, a temperature detection device, comprises: a solution covered by a thin film and frozen, as a frozen solution, in a shape of a mold, wherein on thawing, the frozen solution changes shape to indicate a thaw event has occurred.

[0012] In an implementation, a temperature detection device, comprises: multiple wells in a matrix pattern, wherein each well of the multiple wells comprises a sensor and a frozen solution with different properties than frozen solution in other wells of the multiple wells, and wherein the sensor in each well of the multiple wells are used to determine both a highestPCT Patent Application Attorney Docket No. 57274-0010WO1 temperature reached and a time the temperature detection device has been at or above the highest temperature reached.

[0013] In some implementations, described subject matter can be implemented using a computer-implemented method; a non-transitory, computer-readable medium storing computer- readable instructions to perform the computer-implemented method; and / or a computer- implemented system comprising one or more computer memory devices interoperably coupled with one or more computers and having tangible, non-transitory, machine-readable media storing instructions that, when executed by the one or more computers, perform the computer- implemented method / the computer-readable instructions stored on the non-transitory, computer- readable medium.

[0014] The subject matter described in this specification can be implemented to realize one or more of the following advantages.

[0015] First, keeping an item (e.g., food and pharmaceuticals) at a required temperature range is critical to enhance overall supply chain resiliency, promote energy efficiency, regress climate change, and preserve freshwater resources in core food and pharmaceutical sectors (among others). In these core sectors, cold chain temperature variance can facilitate premature spoilage of an item, taint consumable items with toxins, and cause severe / harmful health effects. The described approach provides tools permitting determination of whether a package or part thereof has breached a given temperature threshold within the cold supply chain (from -90°C to 0°C, selected according to need). Detecting code information from sensors after thawing provides end-to-end food safety, temperature, quality, security, and / or authentication supply chain benefits.

[0016] Second, in some implementations, a sensor does not come in direct contact with a food item. As a result, a sensor, as described in this disclosure, does not need to pass food safety compliance. This is advantageous as safety compliance may be expensive and may hamper use of the sensor. The sensor can be manufactured more cheaply and, therefore, be more widely used. Such widespread use can help solve the current problems of item waste because of perishing during transit.

[0017] Third, described sensor applications can be extended to refrigerated product monitoring (e.g., in the subzero to the 0°C to 8°C range) as well as for -90°C ultra-low frozen product monitoring. Furthermore, refrigerated, frozen and ultra-low frozen sensor use casesPCT Patent Application Attorney Docket No. 57274-0010WO1 extend to other sectors beyond perishable food such as to healthcare cold chain storage such as for monitoring pharmaceutical products (e.g., mRNA vaccines for all three aforementioned temperature ranges). Additionally, the use of these sensors has broad applicability to a myriad of other industries as well as use cases for broad temperature- based monitoring in the business-to- business (B2B) and business-to-consumer (B2C) sectors.

[0018] Fourth, in some implementations, described sensors can be used for quality or tracking of non-frozen items. To limit cost per sensor, elements of sensors can include components already produced at high volume or low cost but configured to generate effective sensor readings indicating item quality or authentication. In some cases, an item quality (e.g., food quality) is not measured directly by a sensor. For example, a sensor can be used to generate readings in an area around an item. Such readings can be processed to determine a quality or authentication of an item.

[0019] Fifth, edible sensors, as well as bio-engineered variants and chemically modified forms (i.e., that are similar to sensors of naturally occurring compounds), are food-safe, being entirely edible, biodegradable (e.g., bio-safe), and of extremely low cost. The sensors can be deployed on food products prior to packaging, on the surface of packages, or distributed within a shipment of packages (such as, within a pallet) to determine whether associated products have thawed.

[0020] Sixth, alternatively, or in combination with applying a dye to a surface, a small amount of food coloring can be injected into an edible food-based gel (e.g., tofu) before flash freezing. Similarly, thawing would be detected in a product by the appearance of color rather than a white food-based gel sample. The described sensors can be added to frozen products without contamination, in almost any location, and used as indicators of food safety. If a changed color is present when a container is opened, then the product can be rejected. Additionally, the described sensors can be used to determine when a product has thawed, for example, in domestic uses, to permit use.

[0021] Seventh, sensors can be modified by the use of any of a range of coatings, if necessitated by specific use cases. By coating a sensor with a thin layer of any non-paper miscible hydrophobic material, a paper-based sensor can be made entirely hydrophobic on one side, meaning that however great the temperature and humidity difference between the ice upon which the paper-based sensor is located and surrounding air, no color change due to adsorption of waterPCT Patent Application Attorney Docket No. 57274-0010WO1 solubilizing or reacting with the dye in the paper is observed because no water is adsorbed. Likewise, the use of a thin film of clear, non-water-soluble tape achieves the same thing, with no atmospheric water being able to permeate the tape to cause a color change.

[0022] Eighth, rather than using a single concentration of saline, organic acid salt, or other frozen solution, and a single volume, a range of frozen volumes and concentrations may be employed using any of the disclosed sensing devices. This technique can result in a thaw detection matrix that provides information on a maximum temperature reached and for how long. Any thaw detection system leading to rejection of a package based on briefly increasing temperature to a point where the very outer layer of packaging has increased above a set point is too sensitive for many applications. By using a matrix of different volumes or different concentrations of a solution, applicability of detection can be improved. By employing a range of volumes or concentrations of solute, a sensor or sensor cluster can help detect characteristics of an item (e.g., a maximum temperature of the item during shipment, whether or not the item likely thawed, how long the item was at a given temperature or within a temperature range, among others). A sensor can detect the thaw detection matrix and use information of the thaw detection matrix to determine information related to an item (e.g., a maximum temperature reached or how long an item was exposed to a given temperature).

[0023] Ninth, by basing a thaw sensor on an irreversible visible change, an indelible record of whether a product or shipment has breached a given temperature is created, meaning that a re-frozen product is not erroneously assumed to be safe because it arrives frozen.

[0024] Tenth, by using visible indicators that can be read using a smartphone, an adaptable system for determination of product safety is created, whereby, with or without a reading device (e.g., a mobile computing device) product safety can be guaranteed. The sensors are in effect resilient to network and wider technology failure.

[0025] Eleventh, the described approach permits multiplexing of sensors for verification (e.g., multiple sensors of the same type to confirm a reading), to convey further information (e.g., a color based sensor alerting a user to a thaw such that they can access another sensor that contains more information, such as an NFC tag), for the determination of more complex thaw information (e.g., how long a package has been above a given temperature or the highest temperature to which it has been raised), and can be overt (e.g., with the arrangement and location of sensors being clearly apparent) or covert (e.g., with the location and arrangement of sensors being hidden or notPCT Patent Application Attorney Docket No. 57274-0010WO1 apparent).

[0026] The details of one or more implementations of the subject matter of this specification are set forth in the Detailed Description, the Claims, and the accompanying drawings. Other features, aspects, and advantages of the subject matter will become apparent to those of ordinary skill in the art from the Detailed Description, the Claims, and the accompanying drawings.PCT Patent Application Attorney Docket No. 57274-0010WO1 DESCRIPTION OF DRAWINGS

[0027] FIG. 1A illustrates an example of an inverted saline pocket, textured surface temperature detection device for thaw detection, according to an implementation of the present disclosure.

[0028] FIG. 1B illustrates an example of a saline pocket textured surface temperature detection device for thaw detection that is a textured side up device of FIG.1A, according to an implementation of the present disclosure.

[0029] FIG. 1C illustrates an example of a saline pocket textured surface temperature detection device for thaw detection where frozen saline solution in FIG.1B has melted, according to an implementation of the present disclosure.

[0030] FIG. 2A illustrates an example of an inverted saline pocket, textured surface temperature detection device for thaw detection, according to an implementation of the present disclosure.

[0031] FIG. 2B illustrates an example of a saline pocket textured surface temperature detection device for thaw detection that is a textured side up device of FIG.2A, according to an implementation of the present disclosure.

[0032] FIG. 2C illustrates an example of a saline pocket textured surface temperature detection device for thaw detection where frozen saline solution in FIG.2B has melted, according to an implementation of the present disclosure.

[0033] FIG.3 illustrates a transition to visibility of dye in a crimped paper sensor device for thaw detection, according to an implementation of the present disclosure.

[0034] FIG.4A illustrates a Siloxane surface grating mold, according to an implementation of the present disclosure.

[0035] FIG.4B illustrates a paraffin wax holographic temperature sensor generated using the Siloxane surface grating mold of FIG. 4A, according to an implementation of the present disclosure.

[0036] FIG.5 illustrates diffusion of a dye into a thawed edible food-based gel, according to an implementation of the present disclosure.

[0037] FIG.6 illustrates diffusion of a colorant from a frozen surface into a thawed edible food-based gel, according to an implementation of the present disclosure.PCT Patent Application Attorney Docket No. 57274-0010WO1

[0038] FIG.7A illustrates dye injection production of a frozen edible food-gel-based thaw sensor, according to an implementation of the present disclosure.

[0039] FIG. 7B illustrates a thawed dye-injection-produced edible food-gel-based thaw sensor where dye in FIG. 7A is diffused and changes the color of the sensor, according to an implementation of the present disclosure.

[0040] FIG. 8A illustrates production of a frozen rice-paper-based, dye-infused thaw sensor, according to an implementation of the present disclosure.

[0041] FIG.8B illustrates a thawed rice-paper-based, dye-infused thaw sensor where dye in FIG.8A is diffused and changes the color of the sensor, according to an implementation of the present disclosure.

[0042] FIG. 9A illustrates a frozen rice-based, dye-infused thaw sensor, according to an implementation of the present disclosure.

[0043] FIG.9B illustrates a thawed rice-based, dye-infused thaw sensor where dye in FIG. 9A is diffused and changes the color of the sensor, according to an implementation of the present disclosure.

[0044] FIG.10A illustrates a frozen tofu-based, dye-infused thaw sensor, according to an implementation of the present disclosure.

[0045] FIG. 10B illustrates a thawed tofu-based, dye-infused thaw sensor where dye in FIG.10A is diffused and changes the color of the sensor, according to an implementation of the present disclosure.

[0046] FIG. 11A illustrates a frozen, freeze-dried, tofu-based, dye-infused thaw sensor, according to an implementation of the present disclosure.

[0047] FIG. 11B illustrates a thawed, freeze-dried, tofu-based, dye-infused thaw sensor where dye in FIG. 11A is diffused and changes the color of the sensor, according to an implementation of the present disclosure.

[0048] FIG.12A illustrates an example of a 96-well plate matrix thaw sensor, according to an implementation of the present disclosure.

[0049] FIG.12B illustrates an example of a 96-well plate matrix thaw sensor which started in a configuration of FIG. 12A and indicates that a package has briefly reached an elevated temperature, according to an implementation of the present disclosure.PCT Patent Application Attorney Docket No. 57274-0010WO1

[0050] FIG.12C illustrates an example of a 96-well plate matrix thaw sensor which started in a configuration of FIG. 12A or FIG. 12B and indicates that a package has remained at an elevated temperature for an extended period of time but did not reach a set threshold, according to an implementation of the present disclosure.

[0051] FIG.13A illustrates an example of a semi-covert 96-well plate matrix thaw sensor, according to an implementation of the present disclosure.

[0052] FIG.13B illustrates an example of a semi-covert 96-well plate matrix thaw sensor which started in a configuration of FIG. 13A and indicates a semi-covert code, according to an implementation of the present disclosure.

[0053] FIG. 14A illustrates an individual component layout of a sponge sensor for thaw event detection, according to an implementation of the present disclosure.

[0054] FIG.14B illustrates a sponge sensor formed by combining elements of FIG. 14A and in use, according to an implementation of the present disclosure.

[0055] FIG.15A illustrates a chamber-type sensor for thaw determination, according to an implementation of the present disclosure.

[0056] FIG.15B illustrates a chamber-type sensor 1500b for thaw determination which is an inverted sensor of FIG.15A, according to an implementation of the present disclosure.

[0057] FIG.15C illustrates a chamber-type sensor for thaw determination after the frozen saline solution of FIG.15B has thawed due to a thaw event, according to an implementation of the present disclosure.

[0058] FIG. 16A illustrates a thaw detection sensor with simple object embedded in ice that cannot be seen or accessed until the ice thaws, according to an implementation of the present disclosure.

[0059] FIG.16B illustrates a thawed thaw detection sensor after saline ice in FIG.16A has melted, according to an implementation of the present disclosure.

[0060] FIG.17A illustrates a frozen thaw sensor created with saline ice and a compressed sponge with a hidden image, according to an implementation of the present disclosure.

[0061] FIG. 17B illustrates a thawed thaw sensor where the saline ice of FIG. 17A has thawed and the compressed sponge has expanded to display the hidden image, according to an implementation of the present disclosure.PCT Patent Application Attorney Docket No. 57274-0010WO1

[0062] FIG.18A illustrates an open grating structure of a thaw sensor with complex optical features, according to an implementation of the present disclosure.

[0063] FIG. 18B illustrates an open grating structure of a thaw sensor with a refractive index-matching-solution frozen to the upper surface of FIG.18A, according to an implementation of the present disclosure.

[0064] FIG. 18C illustrates an inverted open grating structure of a thaw sensor with a refractive-index matching-solution frozen to the top surface of FIG. 18B, according to an implementation of the present disclosure.

[0065] FIG. 18D illustrates an open grating structure of a thaw sensor with a refractive index-matching-solution thawed from the top surface of FIG.18C, according to an implementation of the present disclosure.

[0066] FIG. 19A illustrates a compressed spring thaw sensor with a compressed spring, according to an implementation of the present disclosure.

[0067] FIG.19B illustrates a compressed spring thaw sensor with the compressed spring in FIG.19A in an expanded state, according to an implementation of the present disclosure.

[0068] FIG. 20 illustrates balloon thaw sensors filled with saline solution that are in different colors and frozen into different shapes, according to an implementation of the present disclosure.

[0069] FIG. 21 illustrates an implementation of multiplexed, differently shaped thaw sensors of saline ices with varying thaw points between -18°C and -4°C, according to an implementation of the present disclosure.

[0070] FIG. 22 is a block diagram illustrating an example of a computer-implemented system used to provide computational functionalities associated with described algorithms, methods, functions, processes, flows, and procedures, according to an implementation of the present disclosure.

[0071] FIG. 23 is a flowchart illustrating an example of a method for temperature detection, according to an implementation of the present disclosure.

[0072] Like reference numbers and designations in the various drawings indicate like elements.PCT Patent Application Attorney Docket No. 57274-0010WO1 DETAILED DESCRIPTION

[0073] The following detailed description describes visible indicators for cold chain monitoring and is presented to enable any person skilled in the art to make and use the disclosed subject matter in the context of one or more particular implementations. Various modifications, alterations, and permutations of the disclosed implementations can be made and will be readily apparent to those of ordinary skill in the art, and the general principles defined can be applied to other implementations and applications, without departing from the scope of the present disclosure. In some instances, one or more technical details that are unnecessary to obtain an understanding of the described subject matter and that are within the skill of one of ordinary skill in the art may be omitted so as to not obscure one or more described implementations. The present disclosure is not intended to be limited to the described or illustrated implementations, but to be accorded the widest scope consistent with the described principles and features.

[0074] Worldwide, it is estimated that one-third of food produced is thrown away uneaten, and in the United States up to 40% of all food produced is wasted. This causes a significant environmental and humanitarian burden. In the US, it is estimated that about 95% of this discarded food ends up in landfills. Food waste occurs along the entire supply chain spectrum – from its point of origin (e.g., farm), to a processing production facility, to logistics distribution, to retailers, and to the consumer.

[0075] Reasons for food waste include losses from mold, pests, or inadequate climate control. Food waste is categorized differently based on where it occurs: 1) food “loss” occurs before a perishable item (or product) reaches the consumer as a result of issues in production, storage, processing, and distribution phase and 2) food “waste” refers to food that is fit for consumption, but consciously discarded at the retail or consumption phases.

[0076] When food spoils and / or is wasted, all inputs used in production, processing, transportation, preparation, and storage are also squandered. Therefore, food loss / waste can exacerbate the climate crisis with its significant greenhouse gas (GHG) footprint and wasted freshwater resources. Production, transportation, and handling of food generates significant Carbon Dioxide (CO2) emissions, and when food ends up in landfills, the landfills can generate methane gas, an even more potent GHG. Reducing and preventing food waste can increase food security, foster productivity, spur economic efficiency, promote resource and energy conservation, and help mitigate one or more factor believed to be involved in climate changePCT Patent Application Attorney Docket No. 57274-0010WO1

[0077] It is also estimated that 13% of food produced globally for human consumption was lost in 2023 between harvest and retail, while another 17% of total global food production was wasted in households, in the food service and in retail all together. Furthermore, it is estimated that food that is lost and wasted accounts for 38% of total energy usage in the global food system (e.g., due to ineffective refrigeration and inadequate cold chain management). In addition to food loss / waste, another damaging factor associated with deficient cold chain temperature continuity and associated food loss was that wasted energy consumption accounted for 4% of GHG.

[0078] Keeping an item (e.g., food and pharmaceuticals) at a required temperature range is critical to enhance overall supply chain resiliency, promote energy efficiency, regress climate change, and preserve freshwater resources in core food and pharmaceutical sectors (among others). In these core sectors, cold chain temperature variance can facilitate premature spoilage of an item, taint consumable items with toxins, and cause severe / harmful health effects.

[0079] A supply chain is a network of businesses, processes, and people that move a product from its raw materials to a customer. Supply chains include, but are not limited to, non- cold chains and cold chains. A cold chain adds to a supply chain the use of temperature control, thermal packaging, sensors, tools, and data systems for gathering data, real-time temperature monitoring, and issue mitigation to maintain chilled / frozen / cryogenically frozen product integrity, regulatory compliance, and security. In some implementations, cold chain monitoring encompasses a range of colorimetric and other visible indicators for thaw sensing which utilize (among other materials) food safe and edible components for detection of thaw events in frozen items at any point in the cold chain. Described tools permit determination of whether an item’s package, or part thereof, has breached a given frozen temperature threshold (e.g., with a range from -90°C, or lower, to 0°C) and / or a given chilled temperature threshold (e.g., with a range from 0°C to 4°C) within the cold chain.

[0080] This disclosure is directed toward devices, methods, and procedures for supply chain monitoring, including, in some implementations and where appropriate, a cold chain ecosystem of a supply chain. As will be understood by those of ordinary skill in the art, the disclosed devices, method, and procedures may be applicable to a supply chain, including non- cold chains, cold chains, or other supply chain implementations consistent with this disclosure.

[0081] Thaw Sensors Using Color ChangePCT Patent Application Attorney Docket No. 57274-0010WO1

[0082] In some implementations, sensors to detect temperature can use color changes to indicate a temperature change or changes in other properties. For example, sensors can determine power of Hydrogen (pH), glucose, microbial growth, carbon monoxide, or other analytes. If a color change is sufficient to be visible to the naked eye (e.g., using universal indicator paper), gradations of change can be detectable without the use of another detection system. An example of color changes could include use of binary indicators, such as white spots in water detectors turning from white to blue.

[0083] Techniques can also include using sensors, such as spectrophotometers, to determine a concentration of an analyte. Spectrophotometers operating on mobile computing devices (e.g., smartphones or tablet computers), can provide numerical data to determine a concentration. Sensor readers can include cameras (e.g., operating on a mobile computing device such as a smartphone or tablet computer). In some cases, spectrophotometers can include one or more smartphone cameras. Sensors can be based on fluorescence, the appearance or disappearance of color, or a change in color intensity or wavelength, which can be measured (e.g., in reflectance, transmittance, or absorbance). In some implementations, sensors can include an indicator dye added to liquid (e.g., in solid form as a film, as particulates added to either a solution or a surface, or as soluble dyes that are mobilized by the presence of a solvent that turns paper or another substrate the color of the dye by solubilization and mobilization, and translocation or redeposition thereof).

[0084] In some implementations, holographic gelatine emulsions can be used to determine whether a volume of saline solution has thawed. For example, a concentration of salt (e.g., sodium chloride) can be selected to tailor the melting point of a solution. The melting point can be adjusted to match a melting or thawing point of an item (e.g., a frozen food item or chilled medical or other chemical items, such as pharmaceutical vaccines). The volume of saline solution can be configured with a water sensitive hologram placed on a surface of the volume. In this way, the hologram can provide rapid detection of increasing temperature above a thaw point. In general, sensors for detecting thawing or melting can include other types of sensors consistent with this disclosure without departing from the scope of this disclosure (e.g., sensors operating on different principles or producing different forms of color change).

[0085] In some implementations, sensors for detecting temperature change (e.g., melting or thawing), use a chemical, enzymatic, or physical change that causes a change in absorbance orPCT Patent Application Attorney Docket No. 57274-0010WO1 reflectance wavelength. For example, holographic sensors or pH indicators can be used to indicate a temperature change, such as melting or thawing, based on chemical or physical changes in an item or proxy (e.g., a volume of saline solution used as a proxy to determine melting or thawing of an item with the same or similar thawing / melting point).

[0086] In some implementations, pH sensors with an acid dissociation constant (pKa) range well away from neutral are used. For instance, the pKa of a holographic pH sensor can be based on a pKa of the acid, or base group within an otherwise non-charged hydrogel in which it is incorporated. The range can be tailored from very low pH values (e.g., by using a sulfonic acid) and towards a neutral range (e.g., by using a methacrylic acid) or above (e.g., by using various amines). The charged group acts similarly to a pH buffer with 90% of the protonation or deprotonation, thereof, occurring within 1 pH unit of that pKa value. Swelling or contraction of the hydrogel (imparting change of color of a hologram, that being based on swelling or contraction, thereof) and, therefore, can occur within around 1.5-2 pH units of the pKa value of that charged group.

[0087] By designing a pH sensor hologram with a pKa value well away from neutral, a specific response to a chosen solution can be ensured (e.g., with a hologram incorporating a sulfonic acid group, with a pKa value of approximately pH 2, where an accidental response is unlikely). A specific response can be based on pH (e.g., not a concentration of an acid or base). In some cases, a 0.01M solution of hydrochloric acid (e.g., pH 2, can be used to cause a color change). The acid can be incorporated within a solution of NaCl which can provide control of both a melting point and pH. As an illustrative example, for thaw sensor temperature detection an indicator dye (e.g., chlorophenol red) can be used. Chlorophenol red is an indicator dye that is colored and is around neutral pH (water is also typically around a neutral pH). A sensor using an indicator dye (e.g., included on detector paper) can work at low temperatures (e.g., below 0°C). Such a sensor can be used to detect a thaw of saline solution or other frozen solutions to provide an irreversible indication of thaw detection). By changing the pH of a solution (e.g., by choosing a buffer above or below the pKa value of the indicator, or the degree to which a solution containing formic acid is titrated with potassium hydroxide) a color response can be tailored.

[0088] In some implementations, a color change on hydration of metal salts and organic dyes (e.g., cobalt paper) can be used to indicate thawing or melting. In some implementations,PCT Patent Application Attorney Docket No. 57274-0010WO1 solubilization and translocation of dyes, similar to the mechanism used in detector papers sensitive to chemical warfare agents or other chemical hazards, can be used to detect thawing or melting.

[0089] Textural Thaw Sensors

[0090] In some implementations, saline (e.g., sodium chloride or other salt) solutions can be frozen on a large variety of surfaces, including those manufactured by three-dimensional (3D) printing, embossing, or molding. If such surfaces are contained within simply constructed saline pockets, with gaps such that the solution could drain through the textured material on thawing, then the surface would become visible and detectable either by sight or touch (e.g., using fingers if within a safe temperature range, or by running a stylus across the surface if too cold).

[0091] FIG. 1A illustrates an example of an inverted saline pocket, textured surface temperature detection device 100a for thaw detection, according to an implementation of the present disclosure.

[0092] In FIG.1A, a textured surface 102 and saline solution 104 is incorporated within a saline pocket 106. In the illustrated implementation of FIG. 1A, the textured surface 102 has a ridged surface into which the saline solution 104 is frozen to the textured surface 102 in inverted position. A hollow portion 108 of the saline pocket 106 is facing upward.

[0093] FIG. 1B illustrates an example of a saline pocket textured surface temperature detection device 100b for thaw detection that is a textured side up device of FIG.1A, according to an implementation of the present disclosure.

[0094] In FIG.1B, the device 100b is flipped over with the textured surface 102) facing upward and applied to a package or object (e.g., using an adhesive). In the illustrated implementation of FIG. 1B, the frozen saline solution 104 is at the top of the device 100b and covering the textured surface 102 (e.g., creating a smooth surface and / or obfuscating the textured surface 102). The hollow portion 108 of the saline pocket 106 is facing downward.

[0095] FIG. 1C illustrates an example of a saline pocket textured surface temperature detection device 100c for thaw detection where frozen saline solution in FIG. 1B has melted, according to an implementation of the present disclosure.

[0096] In FIG. 1C, the frozen saline solution 104 has melted and pooled into the hollow portion 108 of the saline pocket 106 on an opposite side of the textured surface 102. As a result, the textured surface 102 is both visible and tactilely detectable (e.g., using a finger or a stylus). The condition of device 100c in FIG.1C indicates that a thaw event has occurred.PCT Patent Application Attorney Docket No. 57274-0010WO1

[0097] In some implementations, the textured surface 102 can be constructed using a hollow or absorbent material (e.g., a sponge) into which thawed saline solution 104 would enter upon thawing. In this implementation, a hollow under the textured surface in the saline pocket may not be necessary (thus resulting in a thinner profile device).

[0098] Turning to FIG. 2A, FIG. 2A illustrates an example of an inverted saline pocket, textured surface temperature detection device 200a for thaw detection, according to an implementation of the present disclosure.

[0099] In FIG.2A, a hollow textured surface 202 and saline solution 104 is incorporated within a saline pocket 204. In the illustrated implementation of FIG. 2A, the hollow textured surface 202 has a ridged surface into which the saline solution 104 is frozen to the hollow textured surface 202 in inverted position.

[0100] FIG. 2B illustrates an example of a saline pocket textured surface temperature detection device 200b for thaw detection that is a textured side up device of FIG.2A, according to an implementation of the present disclosure.

[0101] In FIG. 2B, the device 200b is flipped over with the hollow textured surface 202 facing upward. In the illustrated implementation of FIG. 2B, the frozen saline solution 104 is at the top of the device 200b and covering the hollow textured surface 202 (e.g., creating a smooth surface and / or obfuscating the hollow textured surface 202).

[0102] FIG. 2C illustrates an example of a saline pocket textured surface temperature detection device 200c for thaw detection where frozen saline solution in FIG. 2B has melted, according to an implementation of the present disclosure.

[0103] In FIG.2C, the frozen saline solution 104 has melted and pooled into / been absorbed by the hollow textured surface 202. Note that a small portion of saline solution 104 that is not absorbed is visible in the illustration of FIG.2C in a corner of the saline pocket 204. As a result, the upper portion of the hollow textured surface 202 is both visible and tactilely detectable (e.g., using a finger or a stylus). The condition of device 200c in FIG.2C indicates that a thaw event has occurred.

[0104] In some implementations, a textured surface (e.g., 102 or 202) can be used to facilitate a pattern or symbols (which may be detected visibly or by touch), and only becoming visible upon thawing of a saline solution (e.g., saline solution 104), making for an easily identifiable and tailorable solution for thaw sensing.PCT Patent Application Attorney Docket No. 57274-0010WO1

[0105] In some implementations, soluble dyes or particulates within the saline solution may be used, to either obscure the features of the textured surface when frozen, or to change a color of the saline solution after it has thawed (e.g., to prevent reuse or tampering). For example, if a hollow structure (e.g., hollow textured surface 202) in a saline pocket contained a small volume of red dye, then attempts to realign the surface temperature detection device and refreeze the package can be detected (i.e., by the presence of the dye now diluted into the saline solution after thawing.

[0106] By creating a logo, or an image, on such a surface, complex codes, logos or messages can be used. For example, in some implementations, the textured surface can be replaced by a quick response (QR) code, bar code, or other data code (or even a coded company logo) as chosen, and a pattern can be revealed or modified by thawing. Use of either turbid or highly colored solutions can reveal or hide a patterned surface and offers multiple routes for thaw detection as described. In these implementations, the textured surface can be substantially smooth from a tactile point of view (e.g., not ridged as illustrated in 102 or 202), but still suitable for the previously mentioned QR code, bar code, or other data code.

[0107] In some implementations, a customized concentration of salt can be used in the implementations of FIGS.1A-1C and 2A-2C to modify the freezing point of the saline solution. In addition, more exotic salts (e.g., formats) can be used to lower the freezing point beyond a concentration of saline solution. In some implementations, waxes or oils can be used to generate a color change above a specified temperature (e.g., 0°C).

[0108] Thaw Detection by Color Obfuscation

[0109] In some implementations, color obfuscation can be used in a sensor to detect temperature change. For example, techniques can include freezing saline solution containing a concentration of a material such as titania Avalanche (an iron oxide pigment manufactured by SENSIENT FOOD COLORS) or similar insoluble material in the saline solution. As a suspension rather than ions in solution, this can reduce an effect upon the freezing point of the solution. Using the material can make the saline solution opaque when frozen solution. The opacity can be used as an indicator (e.g., masking the presence of a printed logo, code, or dye deposited underneath). A sample of saline containing such a material can be placed above a selected food coloring where the dye can become visible upon the saline solution melting. Similarly, use of multiple, colored pigments in fluids with similar, or different, melting points can facilitate mixing upon thaw. ThisPCT Patent Application Attorney Docket No. 57274-0010WO1 technique creates a color change based upon physical mixing, necessitating no chemical change to facilitate color change. Such suspensions of pigment may be layered or patterned to create a shift from white (for example if titania is in a visible layer) to orange (if iron oxide is used in a layer below).

[0110] In some implementations, sensors are used for quality or tracking of non-frozen items. To limit cost per sensor, elements of sensors can include components already produced at high volume or low cost but configured to generate effective sensor readings indicating item quality or authentication. In some cases, an item quality (e.g., food quality) is not measured directly by a sensor. For example, a sensor can be used to generate readings in an area around an item. Such readings can be processed to determine a quality or authentication of an item.

[0111] In some implementations, a sensor can include off-the-shelf test strips, or the methodologies encapsulated therein, combined with specific frozen solutions. In some implementations, the sensor can integrate color codes that indicate a quality or authentication of items, such as food items. Commoditized test strips can be inexpensive, and mass produced with inherent sensitivity to 10 or more analytes. Such analytes can give an indication (e.g., 0 or 1 indicating a positive or negative indication). Combining analytes can provide many combinations which can indicate a specific quality of an item or a specific authentication (e.g., 10 analytes generating 0 or 1 results can produce 1024 different combinations). Moreover, if one or more tests generate a range of responses (e.g., a pH indicator outputting variable colors over a range of 4 or more pH units), the number of combinations can be increased further.

[0112] In some implementations, sensors including sensors with one or more test strips are used for thaw detection. In some implementations, sensors are used for additional authentication, (e.g., at point-of-delivery features and functionalities). For example, additional authentication can include authentication after temperature detection by a given sensor. In some implementations, a sensor can be coupled with a color change strip for detection of thaw. For example, a sensor can include a water sensor or a saline sensor. Acids, sugars, or other fluids can be incorporated into solutions used in the sensor (e.g., to trigger a desired color change). By changing concentrations of various elements in a solution, a sensor can be tuned to provide specific indications of quality and / or indications of authenticity and supply chain tracking.

[0113] In some implementations, color readings are used for one or more indications in addition to, or instead of, thaw detection. For example, upon a supply chain product arrival fromPCT Patent Application Attorney Docket No. 57274-0010WO1 its point of origin, an initial color reading can be used to determine if an item has likely thawed based on sensor measurements of a corresponding solution. If an initial reading of a sensor indicates that a solution has not thawed in transit, a user may then remove the sensor and allow the solution of the sensor to thaw before taking a reading of the sensor, e.g., reading of one or more color indicators of the sensor. Data obtained after thawing of the solution can indicate information that is effectively obfuscated during transit. Data obtained after thawing can include information of authenticity, e.g., a covert code shared between sender and receiver of an item. Such codes can be a particular combination of colors integrated in the sensor that are activated, at least in part, during a thawing of the solution.

[0114] Additional data on the frozen state of the monitored product obtained after the thawing occurred within the sensor can be compared with previously obtained data to determine temperature history during logistics, in contrast to the product’s frozen state at the beginning at the supply chain as it leaves a frozen food processing facility. For example, data obtained from a partially thawed sensor can be compared with: 1) a covert and individualized code either sent in advance to an end-user from a point-of-origin shipper prior to an item’s departure, 2) a covert and individualized code that is stored in a sensor’s software that is then used by a recipient to read or confirm a code shown by a partially thawed sensor, and / or 3) a code that is stored (e.g., as individualized data in an near field communication (NFC) device, or similar data communications device, that can be sent alongside or embedded in the sensor).

[0115] By using techniques similar to the thaw-detection techniques, supply chain security or authentication can be achieved (e.g., by measuring a partially thawed sensor after transit is complete without thawing). In combining two or more color change techniques, complex codes can be generated. Sensor readers, such as smartphones configured with an application for reading or interpreting different sensor codes, can perform actions in response to reading a specific code (e.g., send data to a data logger, send a message to a specific recipient, among others). These sensor readers can also determine one or more unique combinations of colors to determine specific information based on the one or more unique combinations (e.g., where one unique combination indicates that an item has originated from location A, another combination indicates that the item has been routed through location B, or another combination indicates that the items was manufactured on, after, or before a specific date). In some implementations, unique combinations can change over time (e.g., as a solution melts). For example, one or more combinations or sensorPCT Patent Application Attorney Docket No. 57274-0010WO1 readings can be generated as a solution melts. A sensor reader can capture data as melting occurs and determine, based on one or more changes over time, one or more items of information. In other implementations, melting is configured to occur at a specific temperature, such that an expected rate of specific changes in codes generated by a sensor while thawing can be compared with actual measurements of codes changing in time.

[0116] Detecting code information from sensors after thawing provides end-to-end food safety, temperature, quality, security, and / or authentication supply chain benefits. In some implementations, a sensor does not come in direct contact with a food item. By not coming in direct contact with a food item, a sensor, as described in this disclosure, does not need to pass food safety compliance. This is advantageous as safety compliance may be expensive and may hamper use of the sensor. The sensor can also be manufactured more cheaply and, therefore, be more widely used. Such widespread use can help solve the current problems of item waste because of perishing during transit. This same sensor application can extend to refrigerated product monitoring (e.g., in the subzero to the 2°C to 8°C range) as well as for -70°C ultra-low frozen product monitoring. Furthermore, refrigerated, frozen, and ultra-low frozen sensor use cases extend to other sectors beyond perishable food, such as to healthcare supply chain storage for monitoring pharmaceutical products (e.g., mRNA vaccines for all three aforementioned temperature ranges). Additionally, the use of these sensors has broad applicability to a myriad of other industries, as well as use cases for broad temperature-based monitoring in the business-to- business (B2B) and business-to-consumer (B2C) sectors.

[0117] Use of Transition Metal Salts for Thaw Detection

[0118] As will be understood by those of ordinary skill in the art, transition metal salts, transition metals being defined as elements whose atoms can form one or more stable ions with partially filled d sub-shells, change color upon hydration. Unpaired d-orbital electrons can be excited to higher energy levels by absorbing visible light of specific wavelengths when interacting with ligands, causing the compound to appear colored due to the reflected light being the complementary color of the absorbed light. The specific ligand can impact upon the color, with, for example, water producing a red complex with cobalt chloride and ammonia producing a blue color. The color can be detected and identified spectrophotometrically using, for example, a spectrophotometer or a suitable smartphone. The exposure of an anhydrous transition metal salt to water, ammonia, or any of a range of other liquids, gases, or vapors of materials with appropriatePCT Patent Application Attorney Docket No. 57274-0010WO1 lone pairs of electrons for liganding (e.g., methanol, ethanol, dimethyl sulfoxide, and pyridine) released upon thawing or as a vapor due to temperature change can be utilized to create irreversible temperature sensors.

[0119] In some implementations, metal salts, or other substances that color when hydrated, can be used in sensors for indicating when an item has likely melted, thawed, or otherwise changed temperature. For example, transition metals, such as some types of salts, can color when hydrated. Metal salts or other substances that change color when hydrated can be relatively inexpensive components which can be important when manufacturing sensors for monitoring a supply chain where additional costs can prevent sensors from being used or widely adopted. In some implementations, metal salts or other substances can be applied within a container sealed with a cap that includes frozen saline solution, where the metal or other substance will change color upon thawing of the frozen saline solution.

[0120] For example, ferrous lactate is a soluble, food safe iron salt that, on hydration with a sodium chloride solution, produces a mixture that is green and that may change color. In some cases, the color can change with time, giving an indication of how long it has been since the sample thawed. Such a substance can be used in a supply chain to determine a temperature change of an item and / or, in other cases, a length of time since that temperature change. Examples of such substance can be found in anhydrous and hydrated iron chloride. In some implementations, other food-safe or non-toxic metal salts, or other substances can be used in sensors without departing from the scope of the disclosure. In some implementations, cobalt (II) chloride can be used in sensors. Cobalt (II) chloride is blue when anhydrous, and pink when hydrated. The color change has been used for detection when and / or if an item has melted or thawed.

[0121] In some implementations, a sensor includes a sheet of paper permeated or coated with cobalt (II) chloride or another anhydrous metal salt that is incorporated at the end of a strip of filter paper, blotting paper, or other porous material that is in contact with a frozen solution of saline, potassium formate, or other material or solvent lowering the freezing point of the solution. If the solution is raised above its freezing point, the material with the salt coating can be used as an indicator to indicate when the solution melts by a change in color.

[0122] In some implementations, a sensor includes an anhydrous transition metal salt such as anhydrous ferrous lactate that is incorporated between a sheet of filter paper (or other porous medium) of which part is in contact with a frozen solution that thaws at a specified temperature,PCT Patent Application Attorney Docket No. 57274-0010WO1 and a clear film allowing it to be viewed. Upon thawing, the color change of the metal salt can indicate a corresponding item with the same or similar melting point is thawing or melting or is otherwise not at a specified temperature or within a temperature range.

[0123] In some implementations, ammonia may be used in place of water alongside anhydrous metal salts. Aqueous ammonia is generally regarded as safe (e.g., by the United States Food and Drug Administration (FDA), and can be used alongside with or in food as long as it is of food grade. Ammonia has a melting point of -77 C, and a boiling point of -33 C. Ammonia can interact with the d-orbitals of anhydrous transition metal salts in a similar way to water, creating bright, vibrant, detectable colors in previously dull or white anhydrous salts. This technique can be used to detect breaching a temperature above either of the two points listed. Alternatively, ammonia vapor released by thawing or vaporizing ammonia can be detected using pH sensing papers, as described above.

[0124] Use of Hydrochromic Inks & Paints

[0125] In some implementations, hydrochromic paint is used in a sensor to detect temperature changes. Paints and inks can be applied with a brush or by printing. When applied to a surface in contact with a volume of ice, such paints do not change color, but a color change is observed when a volume of ice thaws. Thus patterns, words, and security codes (among others) deposited with hydrochromic inks or paints can be made visible or modified by the effect of thawing water, saline, or similar low melting point solutions.

[0126] Using hydrochromic inks or paints can provide a low-cost system for thaw detection. Any code, number, or word can be rendered using such material on the top, bottom, or within containers of frozen mixtures. In some cases, hydrochromic paint that changes from white to clear on addition of water can be used to render code, numbers, or words through masking (e.g., where the code, numbers, or words are printed or otherwise rendered in a color that is visible when the hydrochromic paint or ink changes from white to clear).

[0127] Sensors using hydrochromic ink or paint can be used to construct QR codes, bar codes, or other readable symbols for product authentication and quality determination. Quality determination can include determining whether or not an item has been kept at a specific temperature or has been kept within a specific temperature range, e.g., using a proxy frozen saline volume with properties similar to the item or corresponding to a temperature threshold to be used for quality determination. For example, an item might remain in a given state (e.g., frozen or liquid,PCT Patent Application Attorney Docket No. 57274-0010WO1 at a specific temperature threshold but that temperature threshold indicates degradation of quality or other harmful effects and so should be detected for a quality determination). A specific saline solution can be generated to melt at that temperature threshold. Such melting can be determined by use of one or more of the sensors described in this document.

[0128] Use of Food Coloring & Dyes

[0129] In some implementations, a sensor that includes food coloring and / or dyes (preferably an organic dye) can be used to determine an item’s temperature change. In some implementations the sensor includes a dyeable material (e.g., paper, a food-based gel, editable materials, fabrics, threads, and fibers).

[0130] For example, a sensor that includes a disc of paper, or other porous material, with dye on one side can be placed on a frozen sample of saline or other frozen volume. The disc of paper can be held in place with a cover. Upon thawing, dye in the paper can be dissolved and can permeate through the paper, turning the top surface of the disc of paper the color of the dye.

[0131] In other implementations, spray adhesive can be applied to a sheet of material, such as blotting or filter paper, and covered with dye. For example, the dye can be For Coloring Food (FCF) brilliant blue dye, or another water-soluble dye. A second sheet of material, e.g., blotting or filter paper, can be applied to a surface of the first sheet of material. In some implementations, discs (or any other shape) are cut and adhered to a sheet of clear plastic (such as acetate or PVC). The discs can include a layer of dyed material and a layer of non-dyed material. Furthermore, the discs can be adhered to samples of frozen volumes and can remain un-dyed (e.g., white), until the volume thaws. When the volume thaws, the discs can turn the color of the dye (e.g., blue in the powdered FCF brilliant blue dye) as the dye is mobilized. In some cases, a dye is dissolved and dried into one disc that is layered under another or between two discs. Solubilization redissolves the dye, which is then mobilized, and which is carried by capillary action into the other strip. Starting with a white top layer, techniques described can produce a colored top layer.

[0132] In certain implementations, powdered dye is applied to a roughened paper surface which is folded or crimped into a powder containing envelope or tag, with the powder being held on the rough paper surface and kept in place by folding. In some implementations, edges of an envelope within a sensor, or tag that includes embedded powder, can be sealed by folding and hot pressing or use of adhesive. Upon exposure to melting saline solution, the dye (e.g., FCF brilliant blue) is solubilized and becomes visible.PCT Patent Application Attorney Docket No. 57274-0010WO1

[0133] Turning to FIG. 3, FIG. 3 illustrates a transition to visibility of dye in a crimped paper sensor device for thaw detection 300, according to an implementation of the present disclosure.

[0134] In FIG. 3, crimped paper packet 302 incorporates super-hydrophilic food dye particles (e.g., FCF brilliant blue) and is attached to a surface 304 on a volume of frozen saline solution. As the frozen saline solution thaws, the dye is rapidly solubilized by the aqueous saline solution and becomes visible on the surface of the crimped paper packet 302 through capillary action distributing the dye in the paper.

[0135] Color change packets with folded or crimped surfaces can be employed in such a manner that it is adhered to the top of a thawable solution, or many can be distributed throughout an entire package, such that, when any part of the package is exposed, an immediate color change indicative of thaw is detectable. This technique may be employed with an excess of dye, such that, if the item has thawed, the dye leaches directly into the item (e.g., food). If the dye is a food safe dye, the presence of the dye is merely an indicator that the product may be of impaired quality, but does not itself affect the safety of the item. This technique for thaw detection is suitable for low- cost or high-volume items and can be a part of a packaging solution.

[0136] The use of paper without surface treatments (i.e., sizing – the treatment of paper to optimize the deposition of ink or paint) can facilitate rapid mobilization of a dye throughout the paper, allowing near immediate detection of an aqueous thaw event. Un-sized paper also can be patterned with hydrophobic materials to create images (e.g., QR codes or other symbols that appear in un-patterned areas when the mobilized dye becomes visible). Therefore, whether dye is incorporated as a powder between two layers of paper held in place with adhesive, crimping, or a tape, the technique produces a complex and versatile tool for both covert and overt messaging in thaw detection. Any suitable dyes can be used in the techniques described herein. In some implementations, dyes can include water-soluble dyes with a range of colors. Moreover, dyes, fibers and fabrics can be used to render complex messages or codes in response to detecting thawing.

[0137] In some implementations, dyes that undergo a color change upon hydration or solvation can be used in a sensor for thaw detection. An example dye is crystal violet (also known as methyl violet 10B or hexamethyl pararosaniline chloride), which in dry form is a green powder, becoming purple upon hydration. When incorporated (e.g., by sprinkling) on a paper or cardPCT Patent Application Attorney Docket No. 57274-0010WO1 surface (e.g., using a spray-type adhesive) creates a speckled green sensor that turns purple when the solution is in contact with a volume that has at least partially thawed.

[0138] Indicator Dye Technologies

[0139] In some implementations, and as mentioned earlier, a sensor for temperature detection can include indicator dyes. For example, chlorophenol red can be used in a sensor. Chlorophenol red is an indicator dye that is colored at and around neutral pH (water is typically around neutral pH). A sensor using an indicator dye (e.g., included on detector paper), can work at low temperatures (e.g., below 0°C). Such a sensor can be used to detect thawing of saline or other frozen solutions to give (e.g., an irreversible indication of thaw detection). By changing the pH of a solution (e.g., by choosing a buffer above or below the pKa value of the indicator or the degree to which a solution containing formic acid is titrated with potassium hydroxide) a color response can be tailored.

[0140] Hologram & Grating Technology

[0141] In some implementations, a sensor for detecting temperature can include a hologram, such as a surface grating or depth grating (e.g., a relatively easy to generate Denisyuk grating). For example, a hologram can be included as part of a distinctive and difficult to copy thaw detection system.

[0142] Surface gratings can be produced by depositing a paint (e.g., soluble paint or an ink) and by ablation of deposited material using a pulse laser, among other production techniques. In some implementations, holograms, such as surface gratings, can be configured to create images or codes using a mask. The hologram can be created in a final step before leaving a point of origin, such as a production site or intermediary point along a supply chain. Samples of material can be exposed to light, e.g., laser light, through filters to create logos, words, secure codes, or other symbols (e.g., an indication of item authentication or quality for shipping).

[0143] In some implementations, by using a hand-held pulse laser (e.g., used for hair or tattoo removal) gratings can be constructed on the obverse of a plastic film in a frozen pocket in contact with a frozen volume. This permits production of a hologram on an inner surface of packaging of a frozen pocket through a clear plastic window.

[0144] In some implementations, grating structures can be generated using moldable materials. For example, grating structures (e.g., for indicating item temperature or authentication) can be generated in a range of materials using molding methods. Materials used for molding canPCT Patent Application Attorney Docket No. 57274-0010WO1 include polydimethylsiloxane (or Siloxane) among others (e.g., for use as a mold within which a grating is formed), wax (e.g., poured into a mold in liquid form and removed after hardening), or other moldable materials.

[0145] Turning to FIG. 4A, FIG. 4A illustrates a Siloxane surface grating mold 400a, according to an implementation of the present disclosure.

[0146] In FIG.4A, 402a illustrates grating structures formed in a siloxane mold which are refracting light.

[0147] FIG.4B illustrates a paraffin wax holographic temperature sensor 400b generated using the Siloxane surface grating mold 400a of FIG.4A, according to an implementation of the present disclosure.

[0148] In FIG. 4b, 402b illustrates grating structures formed in paraffin wax which are refracting light.

[0149] In some implementations, sensors can include materials that melt to create irreversible temperature sensors. For example, components, such as animal or synthetic fats, palm oils, cocoa butters, among others can be combined to produce an irreversible temperature sensor that works above a freezing point. For use, components can be combined to generate a spot within a grating where a visual change in the spot can indicate that a temperature threshold has been reached. In some implementations, gratings can be made, at least in part, of acetate or siloxane.

[0150] In some implementations, other structures can be used to indicate a detectable change above a freezing point by using components, such as fats or other substances. For example, a pattern can be generated by combining different materials into a contiguous grating, and when a temperature exceeds a threshold, the pattern can be destroyed (e.g., by partial melting) and can serve as an indication that a temperature has exceeded the threshold.

[0151] In some implementations, Denisyuk holograms can be used in one or more sensors for temperature detection, where the Denisyuk holograms can be degraded by adding water. In some implementations, a solution of potassium tetrachloroaurate is added to a polyvinyl alcohol (PVA) solution. The combined solution is deposited on a plastic film. The deposited solution is allowed to dry, during which time the potassium tetrachloroaurate can degrade, producing gold nanoparticles entrapped by the agarose. When exposed to produce a Denisyuk hologram with a pulse laser to form a grating via laser ablation, a bright and stable hologram can be constructed. When this sample is exposed to liquid water, the grating can be rapidly and irreversibly lost.PCT Patent Application Attorney Docket No. 57274-0010WO1 Therefore, such a hologram (which may contain or be part of a wider security code such as a QR code) can create a thaw sensor that can be deployed to determine whether a shipment has breached a specific temperature point.

[0152] A range of un-crosslinked polymer matrices (e.g., polyethylene oxide, PVA, agar, or pectin) can be employed, and the grating structure (hence the reflectance of the hologram, reliant upon retaining nanometer precision) lost on exposure to aqueous solutions on thawing. In some implementations, a gelatine Denisyuk hologram constructed with silver bromide fringes can be rendered water unstable if stored in light for a period of time, therefore also producing a workable thaw sensitive hologram. Both surface and Denisyuk gratings can be made with images containing logos or security codes as an indication of an item’s authenticity or quality for shipping.

[0153] Edible Materials for Thaw Sensing

[0154] Using edible food-based gels, such as, tofu, alginate, gelatine gels (jelly), starch gels (e.g., nokdu-muk), kissel, agar, carrageen, and / or other edible gels in thaw detection allows the surveillance of thaw by diffusion of coloring / dyes into the food-based gels in response to a thawing event. For example, food colorings that may be frozen in a saline solution or deposited on or in the edible material becoming available for diffusion upon thawing at temperatures between 0°C and 19°C, depending upon a salt concentration. Similarly, depending upon a salt concentration within a food-based gel (e.g., tofu), diffusion of a bright colored soluble food coloring through the food-based gel is possible when it is in a thawed condition, but not when frozen. Thus, a diffusion of a food coloring from a frozen solution through such a food-safe gel is indicative that thawing has occurred.

[0155] Turning to FIG. 5, FIG. 5 illustrates diffusion 500 of a dye into a thawed edible food-based gel, according to an implementation of the present disclosure.

[0156] In FIG. 5, a frozen (initially at -20°C) edible food-based gel (tofu) block 502 is thawed on a surface 504 with a dye powder (e.g., FCF brilliant blue) present on the top surface of the frozen tofu block 502. Due to the thawing (e.g., after 1 hour), the dye 506 has diffused from the surface to within the tofu block 502.

[0157] Food-based gels can be used in a raw state, or after drying (e.g., air drying, drying by heating, or freeze-drying), and can be produced using a range of methods. Tofu, for example, is made using soy milk, which is a colloidal protein matrix / suspension made by soaking, mashing, and cooking soybeans prior to filtering. A liquid phase is then cooked to produce stable soy milk,PCT Patent Application Attorney Docket No. 57274-0010WO1 which is used to produce a solid colloid, tofu, by coagulation, using either divalent metal salt ions (calcium and / or magnesium chlorides and sulfates are traditional), curdling using acid (e.g., vinegar or lemon juice), and / or an enzyme, prior to filtering and pressing. The coagulant chosen, alongside a time and method of pressing, creates tofu with specific physical and flavor profiles. In addition, a capacity of the tofu to absorb flavors and colors also depends on time, texture, and coagulation. Chemical crosslinking of the tofu is a critical factor in flavoring and coloring compound absorption and governs a rate that the compounds can diffuse into the food-based gel. Therefore, careful tailoring of tofu can be used to produce a material that acts as a chromatographic medium for diffusion and separation of different colored compounds, and a time for a colored material to diffuse a set distance (and become visible if diffusing to a surface, for example) can be tailored by a specific selection of a coagulant, pressing conditions, and time.

[0158] By careful selection of food-safe and bio-safe material and solutes with known rates of diffusion within the food-based gel, both simple thaw sensors (e.g., indicating that a product has been above a known temperature for sufficient time for a colored solution to thaw and perfuse through an initially frozen or dried edible gel) and time-temperature sensors (i.e., where a time that a product has spent above a set thaw point is measurable by how much the color has diffused into a gel) can be constructed.

[0159] The edible sensors, as well as bio-engineered variants and chemically modified forms (i.e., that are similar to sensors of naturally occurring compounds), are food-safe, being entirely edible, biodegradable (e.g., bio-safe), and of extremely low cost. The sensors can be deployed on food products prior to packaging, on the surface of packages, or distributed within a shipment of packages (such as, within a pallet) to determine whether associated products have thawed.

[0160] In some implementations, a thin section of an edible food-based gel (e.g., tofu) is frozen and placed on a frozen solution of food coloring. In another implementation, the thin section of an edible food-based gel is placed on a sample of dry or powdered food coloring, or the dry or powdered food coloring is deposited thereupon. The food-based gel may be made with a customized concentration of salt to modify its freezing point, or it may be dried before being placed upon the food coloring within a saline solution. Alternatively, or in combination with, food coloring is incorporated into the food-based gel (e.g., wet, or dried), on the underside, prior to freezing, with the food-based gel then placed upon the frozen saline.PCT Patent Application Attorney Docket No. 57274-0010WO1

[0161] Turning to FIG. 6, FIG. 6 illustrates diffusion 600 of a colorant from a frozen surface into a thawed edible food-based gel, according to an implementation of the present disclosure.

[0162] In FIG. 6, a frozen edible food-based gel (tofu) block 602 is thawed on a frozen surface 604 of colorant (e.g., beetroot juice), where both were initially frozen at -20°C. Due to the thawing (e.g., after 20 minutes), the surface 604 (beetroot juice) has diffused from the surface 604 throughout the tofu block 602.

[0163] In some implementations, cubes (or other shapes) of a food-based gel (e.g., tofu) may be injected with a solution or a powder containing a food coloring, and samples rapidly (i.e., seconds to a small number of minutes, depending on a size of food coloring particles) frozen before the food coloring becomes visible (i.e., faster than a time it would take food coloring to diffuse to the surface of the food-based gel). The cubes may be incorporated freely adjacent to, or alongside, food within a shipment to provide visible feedback as to whether a thawing event has occurred.

[0164] In some implementations, cubes of different sizes may be injected with a same or different colorants and included in a single package. Hence, a color and size of cubes that display color, and colors shown, can indicate how long a part of the package has spent above a pre-selected thaw point.

[0165] Turning to FIG.7A, FIG.7A illustrates dye injection production of a frozen edible food-gel-based thaw sensor 700a, according to an implementation of the present disclosure.

[0166] In FIG.7A, an edible food-based-gel (e.g., tofu) block 702a is injected with a dye 704a. The tofu block 702a is rapidly frozen before the dye 704a can diffuse to the surface of the tofu block 702a.

[0167] FIG. 7B illustrates a thawed dye-injection-produced edible food-gel-based thaw sensor 700b where dye in FIG.7A is diffused and changes the color of the sensor, according to an implementation of the present disclosure.

[0168] In FIG.7B, the edible food-based-gel (e.g., tofu) block 702a that is injected with the dye 704a is thawed. The dye 704a diffuses to the surface of the tofu block 702a and the tofu block 702a changes to the color of the dye 704a.

[0169] In some implementations, differently sized food gel particles can be incorporated into food packaging. Each particle size is associated with a different colorant of food coloring. Therefore, packages in which red cubes are found may be deemed to have been above a thaw pointPCT Patent Application Attorney Docket No. 57274-0010WO1 for time (x), smaller particles with a yellow coloring may have only been thawed for time (y). Accordingly, the use of such sensors that are distributed within a load can indicate where thawing has occurred and whether a given time threshold has been exceeded.

[0170] In addition to tofu, a significant range of similar edible materials can also be used (e.g., agar, alginate, and other food-based gels). Additionally, natural compounds, bio-engineered materials, and chemically modified natural and synthetic edible materials can be used. Edible materials can be based on easily and inexpensively available vegetable products, such as dried mushrooms, apples, parsnips, and other fibrous dried foods.

[0171] In some implementations, edible materials can be cut into a sheet form with food coloring deposited as, for example, a powder on one side, and the side with the deposited food coloring can be placed in contact with the frozen saline solution or on the opposite side. When the ice melts, the saline solution diffuses through the edible sensor, hydrating it, and the food coloring dissolves to produce a visible color change. Other edible materials that can be used include cooked rice (e.g., compressed into cakes or sheets), rice paper and other papers made from fibrous edible materials, mycoprotein (e.g., Quorn) as well as other food-based components such as dried cheese and minced cooked beans (which may also be compressed into cakes or sheets).

[0172] Turning to FIG. 8A, FIG. 8A illustrates production of a frozen rice-paper-based, dye-infused thaw sensor 800a, according to an implementation of the present disclosure.

[0173] In FIG. 8A, rice paper 802a coated with a dye powder (e.g., FCF brilliant blue) 804a and frozen (e.g., at -20°C) to a saline ice surface 806a.

[0174] FIG.8B illustrates a thawed rice-paper-based, dye-infused thaw sensor 800b where dye in FIG.8A is diffused and changes the color of the sensor, according to an implementation of the present disclosure.

[0175] In FIG. 8B, the rice paper 802a coated with the dye powder is thawed. Upon thawing, the dye 804a diffuses within the rice paper 802a as the saline ice surface 806a melts. The dye 804a becomes visible.

[0176] In some implementations, additional other edible food-based materials can be incorporated into the sensor to act as a wick for thawed solutions, and to which a food dye can be attached or incorporated in powdered form. The additional other edible food-based materials can also be added in solution, either in ice or within the body of the sensor. Fresh, frozen, and freeze- dried materials (or combinations thereof) may be employed based on a selection of a specificPCT Patent Application Attorney Docket No. 57274-0010WO1 requirements of a thaw sensor in specific applications. For example, for a sensor designed to determine whether a shipment has been above a given thaw point for a set amount of time, fresh, frozen, or wet tofu can be used, with food colorings that diffuse more slowly (e.g., over several minutes). For rapid thaw detection, freeze dried tofu through which solutions diffuse more rapidly (e.g., solubilizing, or diffusing food colorings more rapidly, creating a visible color change) may be preferable.

[0177] Production of Tofu

[0178] Generally, soy milk may be produced using standard extraction processes (i.e., soaking, blending, cooking the mixture, straining, and cooking the mixture) and then coagulating the mixture using a mixture of calcium and magnesium sulphates.

[0179] Tofu and Dried Tofu (or Other Edible Gel) Implementations

[0180] In an implementation, after molding and draining, tofu was frozen into 1.5cm cubes, and the frozen tofu was applied, at -20°C, differently colored materials (e.g., beetroot juice, dry FCF brilliant blue, and FCF brilliant blue solution; each frozen at -20°C) and allowed to thaw. All tofu samples took on the color of thawing solutions. The beetroot wicked very rapidly into the tofu while the FCF brilliant blue solution produced a slower response. The powdered FCF brilliant blue dissolved as the tofu thawed and diffused very slowly into the tofu sample (i.e., less area of the sample was colored in the same amount of time when compared to the beetroot and FCF brilliant blue solution, meaning that a rate of diffusion of the powdered FCF brilliant blue was slower). The rate of a sample taking on color, as in distance of dye front per unit time, is based on complex parameters, including how much of a sample cube has thawed and an ionic state of the sample cube (e.g., due to different production methods).

[0181] These figures illustrate that a thin layer of tofu or other edible gel can produce a simple method for detecting thaw in a food-safe and bio-safe manner. Placing a thin, frozen sample of tofu on a frozen solution of food coloring is a straightforward means of producing a sensor that can be used in or on a food product.

[0182] Calcium Alginate Implementation

[0183] In an implementation, 0.5g of sodium alginate was mixed with 30ml room temperature distilled water and warmed until a thick solution was produced and there was no turbidity indicating undissolved alginate.PCT Patent Application Attorney Docket No. 57274-0010WO1

[0184] 1g of calcium lactate was dissolved in 40ml of distilled water. Both solutions were allowed to cool to room temperature.

[0185] 0.5g of titanium dioxide powder (food grade) was added to 10ml of sodium alginate solution.

[0186] 5ml was dispensed on to the surface of aluminum foil and spread to a thickness of roughly 0.3mm. Likewise, another sample of sodium alginate without any titanium dioxide was spread on to aluminum foil. Both samples were immersed in calcium lactate solution for 4 minutes, setting the alginate as calcium alginate, and were removed and washed. Once the surface moisture had evaporated the samples of white and clear alginate were peeled off the foil and left on greaseproof paper to dry.

[0187] Once dry, the surfaces of both samples were roughened slightly with sandpaper (e.g., 100 grit sandpaper with 5 strokes in 1 direction, followed by turning 90 degrees and performing 5 strokes in that direction), and FCF brilliant blue dye powder applied. Excess powder was shaken off, and the samples placed on to flat surfaces of frozen saline solution (powder side up) at 20°C.

[0188] The samples were left for 2 hours and removed from the freezer. There were no visible changes in the samples between being put into the freezer and being taken out.

[0189] Upon thaw, the samples changed color from colorless to blue (i.e., the sample without titania) and from white to blue (i.e., the sample with titania) within 2 minutes of solution becoming visible on the surface of the ice.

[0190] Rice Paper Implementation

[0191] 1.5cm squares were cut from sheets of TUFOCO Vietnamese rice paper, and the surfaces gently roughened using sandpaper (e.g., 100 grit sandpaper).

[0192] FCF Brilliant blue dye powder was dispensed onto the surface and the excess dye powder shaken off.

[0193] Samples (dye powder side up) were placed on top of a frozen saline solution -20°C.

[0194] The samples were left for 2 hours and removed from the freezer. There were no visible changes in the samples between being put into the freezer and being taken out.

[0195] Upon thaw, the sample turned blue before any visible solution could be seen on the surface of the ice.

[0196] Dried Apple ImplementationPCT Patent Application Attorney Docket No. 57274-0010WO1

[0197] Apples were thinly sliced (e.g., approximately 4mm) and dried in a domestic food dehydrator before storage in an airtight container.

[0198] Samples were removed, trimmed, and squeezed between strips of wood using G- clamps to flatten them.

[0199] After 1 hour flattening, FCF brilliant blue dye powder was applied. Excess powder was shaken off, and the samples (dye powder side up) were placed on to flat surfaces of frozen saline solution at -20°C.

[0200] The samples were left for 2 hours and removed from the freezer.

[0201] There were no visible changes in the samples between being put into the freezer and being taken out.

[0202] Within 15 minutes of liquid solution appearing on the ice, the apple sample turned blue.

[0203] Dye Injection Method Implementation

[0204] As previously described, alternatively, or in combination with applying a dye to a surface, a small amount of food coloring can be injected into an edible food-based gel (e.g., tofu) before flash freezing. Similarly, thawing would be detected in a product by the appearance of color rather than a white food-based gel sample. The described sensors can be added to frozen products without contamination, in almost any location, and used as indicators of food safety. If a changed color is present when a container is opened, then the product can be rejected. Additionally, the described sensors can be used to determine when a product has thawed, for example, in domestic uses. For example, when sample cubes have all changed color, the product has thawed sufficiently to use.

[0205] Multiple Colorings Framework

[0206] In some implementations, an edible sensor can use multiple colorings at once. In these cases, the tofu can operate as a chromatographic medium, and the difference in rate of movement of, for example, FCF brilliant blue and beetroot juice through the medium can result in chromatographic separation. In doing so, the sensors can operate as a time-temperature sensor. When using 2 (or more) colors, the time for each coloring to appear on the top surface of a single sample can produce different colors at different times during thawing, which operates as a time / temperature sensor based on changing colors. Food colors with subtly different ionic charge at a given pH value and size (i.e., molecular size / weight) can be utilized for this use, to maximizePCT Patent Application Attorney Docket No. 57274-0010WO1 differences in the wicking rate into the tofu (i.e., hydrophobic / hydrophilic interactions). How tofu (or other gels that can be used) is produced can impact both its freezing point and its properties as a chromatographic medium. In some implementations, production parameters can include, but are not limited to, how soy milk is treated in production of tofu (e.g., whether calcium or magnesium crosslinking or acid separation of the protein (curdling)), pressing time and amount of pressure used, freezing rate and temperature, and concentration of salt in storage solution after production.

[0207] Heat-Labile Colorings Framework

[0208] Alternatively, or in combination with their use in thaw sensing, heat labile colorings can be used as a determinant of cooking efficacy in frozen foods. The heat-liable colorings can be incorporated in a food product, their visibility on the surface of the food product when opening the packaging acting as an indicator that the food has thawed in transit. Additionally, degradation of the heat-labile colorings while cooking the food product demonstrates that the food product is thoroughly cooked for consumption. As an example, food colorings such as anthocyanins can be used in this manner. The degradation while cooking is counterintuitive to most who work with food colorings because the food-coloring industry typically focuses on producing coloring agents that are as heat-stable as possible.

[0209] Particulates for Thaw Detection Implementation

[0210] Similar to flat sheets, or essentially planar materials for thaw detection, where a food coloring may be on one or other surface or between surfaces such that on thaw it becomes visible, particulates of any of the materials thus far disclosed (and others) can be used for the creation of thaw sensors. For example, ice (water or saline) can be crushed, such that the particles are mixed therewith, or by locating the particles above, underneath, or alongside the ice. When the solution has thawed, color is revealed by solubilization of the dye particles and their diffusion onto the particulates and thawing ice.

[0211] For example, 1 teaspoon of uncooked white Basmati rice was placed on a sheet of sandpaper (e.g., 100 grit sandpaper) and rubbed with another sheet of sandpaper for 10 seconds to create an abraded surface. The rice was then dropped into a glass jar (e.g., with a small spoon – approximately 1 / 8 teaspoon) full of FCF brilliant blue food coloring. The jar was then placed in a freezer at -20°C along with a saline solution, and both were frozen separately. After freezing, the saline solution ice was removed and crushed, before returning the crushed saline solution ice to the freezer to ensure it was fully frozen. After a further 15 minutes, the saline solution ice wasPCT Patent Application Attorney Docket No. 57274-0010WO1 poured into another small container with 20 grains of rice that had been mixed with the food coloring, and again frozen for 2 hours. After this time the saline solution ice / rice mix was removed from the freezer, and white grains of rice in the mix could be observed. As the saline solution ice started to thaw, blue dye very rapidly dissolved from the rice, creating a large blue colored zone indicating that thaw had occurred.

[0212] While simple, raw materials such as dry rice, rolled oats, or wheat grains may be used for this purpose, complex and cooked materials (such as dried cooked lentils, freeze-dried tofu particles, puffed rice, and ground crackers) may be employed and loaded with soluble food colorings as integrable indicators of thawing.

[0213] Turning to FIG. 9A, FIG. 9A illustrates a frozen rice-based, dye-infused thaw sensor 900a, according to an implementation of the present disclosure.

[0214] In FIG.9A, crushed saline solution ice 902a is mixed with rice 904a that has been mixed with a dye powder (e.g., FCF brilliant blue) and frozen (e.g., at -20°C). While frozen, the dye powder does not diffuse into the rice 904a.

[0215] FIG.9B illustrates a thawed rice-based, dye-infused thaw sensor 900b where dye in FIG.9A is diffused and changes the color of the sensor, according to an implementation of the present disclosure.

[0216] In FIG.9B, the crushed saline solution ice 902a has started to thaw. Upon thawing, the rice 904a that has been mixed with a dye powder (e.g., FCF brilliant blue) begins to absorb diffusing dye and dye diffuses 902b into the thawing saline ice 902a.

[0217] Freeze-Dried Tofu for Thaw Detection Implementation

[0218] Half-a-gram of FCF brilliant blue food coloring dye was added to 100ml of saline solution (as defined above) and frozen in 5ml aliquots. Saline solution without dye was also frozen in 5ml aliquots.

[0219] MISUZU freeze-dried tofu was broken into pieces around 1mm in diameter using a dry pestle and mortar, with a finer powder removed by sieving. One small spoon (e.g., approximately 1 / 8 teaspoon) full of FCF brilliant blue food coloring powder was added to 2g of the powdered, crumbled, freeze-dried tofu, and shaken for 30 seconds before sieving to remove any unattached powder. The tofu containing blue dye particles was tightly sealed in a jar and frozen, along with the saline solution samples.PCT Patent Application Attorney Docket No. 57274-0010WO1

[0220] Frozen plain saline solution samples were broken up using a snow cone maker, and returned to the freezer to create a rough saline surface. After the broken-up saline solution samples had refrozen, the broken-up saline solution samples were removed and freeze-dried tofu particles incorporating dry powdered dye were removed from the freezer and placed on the rough saline solution surface. This combination was returned to the freezer and left for 2 hours before removal.

[0221] Upon removal, no color change could be seen. Within 2 minutes, and as soon as the saline solution began to thaw, the samples of tofu turned bright blue. As the sample continued to thaw, the entire surface of the samples of tofu became blue as the dye diffused out further.

[0222] Turning to FIG. 10A, FIG. 10A, FIG. 10A illustrates a frozen tofu-based, dye- infused thaw sensor 1000a, according to an implementation of the present disclosure.

[0223] In FIG. 10A, crushed saline solution ice 1002a is mixed with tofu 1004a that has been mixed with a dye powder (e.g., FCF brilliant blue) and frozen (e.g., at -20°C). While frozen, the dye powder does not diffuse into the tofu 1004a.

[0224] FIG.10B illustrates a thawed tofu-based, dye-infused thaw sensor 1000b where dye in FIG.10A is diffused and changes the color of the sensor, according to an implementation of the present disclosure.

[0225] In FIG. 10B, the crushed saline solution ice 1002a has started to thaw. Upon thawing, the tofu 1004a that has been mixed with a dye powder (e.g., FCF brilliant blue) begins to absorb diffusing dye and dye diffuses 1002b into the thawing saline ice 1002a.

[0226] In another implementation, samples of un-dyed, freeze-dried tofu were prepared by cutting with a finely serrated knife (e.g., 0.4mm thick).

[0227] The un-dyed, freeze-dried tofu was placed on frozen saline containing a dye (e.g., FCF brilliant blue), and returned to a freezer. Two hours later, this combination was removed from the freezer, and no blue color could be seen on the surface. When allowed to thaw, within 2 minutes of liquid saline being visible on the surface of the ice, blue food coloring could be seen to perfuse through the dried tofu to the surface thereof, producing a white to blue color change.

[0228] Turning to FIG.11A, FIG.11A illustrates a frozen, freeze-dried, tofu-based, dye- infused thaw sensor 1100a, according to an implementation of the present disclosure.

[0229] In FIG. 11A, saline solution ice 1102a is mixed with a dye powder (e.g., FCF brilliant blue) and a sample of freeze-dried tofu 1104a is place on the surface of the saline solutionPCT Patent Application Attorney Docket No. 57274-0010WO1 ice 1102a and frozen (e.g., at -20°C). While frozen, the dye powder does not diffuse into the freeze- dried tofu 1104a.

[0230] FIG. 11B illustrates a thawed, freeze-dried, tofu-based, dye-infused thaw sensor 1100b where dye in FIG. 11A is diffused and changes the color of the sensor, according to an implementation of the present disclosure.

[0231] In FIG.11B, the saline solution ice 1102a has started to thaw. Upon thawing of the saline ice 1102a mixed with a dye powder, the freeze-dried tofu 1104a absorbs an aqueous saline solution 1102a and dye. The dye diffuses 1102b within the freeze-dried tofu 1104a.

[0232] Edible & Food-Safe Materials with Paper Based Sensors Implementation

[0233] The use of edible materials in thaw sensing is not restricted solely to fully edible sensors, and they can be combined with, for example, paper and cloth-based sensors. Filter paper sensors using FCF brilliant blue dye in a crimped paper square (e.g., FIG.3) were coated on one side variously with edible coconut oil or cocoa butter, food-safe petroleum jelly (e.g., VASELINE), and bio-safe cellulose tape, with the paper side being placed on frozen saline solution and allowed to thaw. The presence of hydrophobic coatings prevented any interaction of the sensor with water dropped from above and with any condensation from atmospheric water, without making the paper samples environmentally hazardous or toxic. Likewise, such edible and food-safe coatings can be used alongside any of the methods described above (e.g., applied to rice paper or freeze dried tofu). Food-safe and bio-safe materials can include, but are not limited to, coconut oil, coco butter, palm oil animal fats, food safe petroleum jelly, and food-grade waxes.

[0234] Edible and food-safe oils can also be used to pattern the surface of paper-based sensors. A crimped paper FCF brilliant blue sensor as described above was patterned with melted coconut oil, applied with a brush, leaving a single spot in the center. This was allowed to cool, and the sensor then placed on frozen saline solution. The oil, being applied as a liquid rather than spread in semi-solid form, permeated the paper and created zones that remained permeable to thawed solution and zones that were not. As the saline thawed, the central spot turned blue while the outer areas remained white. This method may be employed to create QR codes, bar codes, letters, numbers, or other patterns / messages by printing the oils.

[0235] Use of Coated Substrates to Prevent Adsorption of Atmospheric Moisture

[0236] The sudden exposure of a very cold, hydrophilic materials to higher temperature atmospheric air invariably leads to the formation of condensation at the interface. In the case of aPCT Patent Application Attorney Docket No. 57274-0010WO1 paper-based thaw sensor formulated to respond to water from melting water, saline, or other ice, this can produce false positive detection results.

[0237] Sensors can be modified by the use of any of a range of coatings, if necessitated by specific use cases. By coating a sensor with a thin layer of any non-paper miscible hydrophobic material, a paper-based sensor can be made entirely hydrophobic on one side, meaning that however great the temperature and humidity difference between the ice upon which the paper- based sensor is located and surrounding air, no color change due to adsorption of water solubilizing or reacting with the dye in the paper is observed because no water is adsorbed. Likewise, the use of a thin film of clear, non-water-soluble tape achieves the same thing, with no atmospheric water being able to permeate the tape to cause a color change.

[0238] Materials used can be essentially food safe but indigestible (e.g., petroleum jelly), food safe and edible vegetable based fats (e.g., such as coconut oil, cocoa butter, or solid palm oil fractions), and animal fats (e.g., bees wax, pork or beef fat). Plastic tapes (e.g., polypropylene) or biologically based tapes (e.g., cellophane) using off-the-shelf pressure adhesive backings can likewise be applied to the surface of paper.

[0239] The described technique is not restricted to paper-based sensors, as the coating of freeze-dried tofu using aforementioned oils, or covering layers of dye loaded rice with tape (for example) is possible. A correct means of excluding atmospheric moisture from sensors must always be application driven and depends upon conditions in which a sensor is required to operate.

[0240] Note that with thin films of oils, a range of materials that is available for use is high. Coconut oil, bees wax, cocoa butter and petroleum jelly are familiar materials known to be white but almost opaque, but when spread thin they are almost entirely clear.

[0241] Potassium Acetate & Potassium Format Solutions for Thaw Detection in The Cryogenic

[0242] Range

[0243] Other solutions can be configured for applications of detecting temperatures below a threshold (e.g., -20°C). In these ranges, some impurities for solutions might not behave in a way suitable for measurement (e.g., even when saturated can freeze at around -20°C making detection of lower temperatures difficult). Both potassium acetate and potassium formate are low toxicity (with potassium acetate being a common food additive) and can be used to make aqueous solutions with freezing points as low as -95°C.PCT Patent Application Attorney Docket No. 57274-0010WO1

[0244] In some implementations, a method for generating solutions extended over a cryogenic range can be used. Solutions can be prepared by various means, such as precise mixing of solvents with water or by precise titration of different solutions of weak acids (e.g., acetic acid or formic acid - with sodium or potassium hydroxide). Mixing or titration can provide precise concentrations of salts.

[0245] In some implementations, solutions are frozen after preparation to serve as indicators of temperature change. In some cases, solutions are frozen rapidly enough to prevent salts from precipitating out. As a first example, a portion of saturated sodium chloride solution can be frozen by being placed in a freezer at -20°C. The first example can lead to partitioning of high and low concentration solutions and uneven thawing. Therefore, freezing solutions according to the first example may produce imprecise temperature sensors. In contrast, a second example illustrates a technique to help ensure temperature sensing accuracy. In the second example, a portion of a solution can be exposed to a cryogen (e.g., liquid nitrogen), or such cryogenic freezing agent can be applied over the portion of the solution to rapidly freeze the solution. The rapid freezing can help keep the solution homogeneous. Using rapid freezing techniques can also be efficient because similar freezing methods may be used for freezing food or other items for which temperature sensing is being used.

[0246] Overview of Multiplexed Thaw Sensors

[0247] Rather than using a single concentration of saline, organic acid salt, or other frozen solution, and a single volume, a range of volumes and concentrations may be employed using any of the disclosed sensing devices. This technique can result in a thaw detection matrix that provides information on a maximum temperature reached and for how long. Any thaw detection system leading to rejection of a package based on briefly increasing temperature to a point where the very outer layer of packaging has increased above a set point is too sensitive for many applications. By using a matrix of different volumes or different concentrations of a solution, applicability of detection can be improved. By employing a range of volumes or concentrations of solute, a sensor or sensor cluster can help detect characteristics of an item (e.g., a maximum temperature of the item during shipment, whether or not the item likely thawed, how long the item was at a given temperature or within a temperature range, among others). A sensor can detect the thaw detection matrix and use information of the thaw detection matrix to determine information related to anPCT Patent Application Attorney Docket No. 57274-0010WO1 item (e.g., a maximum temperature reached or how long an item was exposed to a given temperature).

[0248] In some implementations, a matrix of solutions, such as solutions that include increasing amounts of sodium chloride up to saturation, is used. In some implementations, each different solution is included in one or more different volumes. Saturated sodium chloride solution has a freezing point of -19°C, while pure water freezes at 0°C, therefore a gradation of freezing points can be generated by a matrix of solutions. However, the time it takes for the ice to begin melting also depends on an outside temperature and volume of ice, with thin films melting more rapidly than larger volumes. By varying both volume and salinity of samples, a matrix recording characteristics of an item can be generated (e.g., a matrix can indicate the highest temperature of an item, the overall cold storage properties of the shipment, such as the length of time the item has been exposed being determined by the largest volume of saline at a particular temperature point melted).

[0249] Turning to FIG. 12A, FIG. 12A illustrates an example of a 96-well plate matrix thaw sensor 1200a, according to an implementation of the present disclosure.

[0250] In FIG. 12A, the matrix thaw sensor 1200a is used to demonstrate exposure to different temperatures, with increasing salt concentrations in wells 1202a from the bottom to the top of each well plate, and increasing in volume from left to right. The well plate matrix thaw sensor 1200a indicates that a package has remained below -20°C.

[0251] FIG.12B illustrates an example of a 96-well plate matrix thaw sensor 1200b which started in a configuration of FIG.12A and indicates that a package has briefly reached an elevated temperature, according to an implementation of the present disclosure.

[0252] In FIG. 12B, the pattern of activated wells 1202b indicates that a package has briefly reached -6°C.

[0253] FIG.12C illustrates an example of a 96-well plate matrix thaw sensor 1200c which started in a configuration of FIG.12A or FIG.12B and indicates that a package has remained at an elevated temperature for an extended period of time but did not reach a set threshold, according to an implementation of the present disclosure.

[0254] In FIG.12C, the pattern of activated wells 1202c indicates that a package remained at -12°C for an extended period of time, but did not reach a threshold of -9°C.PCT Patent Application Attorney Docket No. 57274-0010WO1

[0255] Other numbers of wells in a well plate are also considered to be within the scope of this disclosure and based on, for example, sensor application needs and sensitivity of detection. While wells in FIGS.12A-12C are arranged in a linear matrix, other well 1202a arrangements are possible on a well plate. Detection spots can be readable (e.g., using a smartphone or other device).

[0256] In some cases, obfuscation techniques can be used. For example, it may be desirable to create a complex array of spots where a storage history of a package cannot be determined by eye. In an example, a matrix of solution concentrations or volumes can be arranged within a linear well arrangement, but in a non-linear fashion to permit formation of complex thaw patterns that can be monitored by use of a mobile computing device reader, such as a smartphone or other mobile computing device using a software application. Monitored information can be provided to a supplier and can be coupled with other supply chain control features (e.g., QR coding of a shipment ID or authentication).

[0257] Turning to FIG. 13A, FIG. 13A illustrates an example of a semi-covert 96-well plate matrix thaw sensor 1300a, according to an implementation of the present disclosure.

[0258] In FIG.13A, the plate matrix thaw sensor 1300a is shown on a package at the point of shipping (e.g., a food product is packaged in a frozen state). No code is visible at the point of shipping.

[0259] FIG.13B illustrates an example of a semi-covert 96-well plate matrix thaw sensor 1300b which started in a configuration of FIG. 13A and indicates a semi-covert code, according to an implementation of the present disclosure.

[0260] In FIG. 13B, a semi-covert code 1302b after shipping is readable by a mobile computing device reader. For example, the semi-covert code 1302b can indicate that a thawing condition has occurred during the shipping process and indicate temperatures and / or storage profile conditions that have changed during shipping.

[0261] In some implementations, QR codes (or similar security techniques) can be used for determination of defrosting. For example, a printed QR code can be included alongside a sensor. The QR code can be adhered alongside or on the same film as a sensing system. In some implementations, color changing technology can be incorporated into one or more secure codes. For example, a color can be read alongside a QR code, where the color can provide additional data that is recorded with the code itself. As a color of the foreground or background of the code changes, a unique dimension can be added to reading the code, increasing complexity to preventPCT Patent Application Attorney Docket No. 57274-0010WO1 forging, or providing an indication of authenticity or quality along a supply chain. In some implementations, techniques can include changing or erasing part of a QR code to create a different code or creating overlapping QR codes in different colors.

[0262] Having multiple unique methods for detection of thawing can permit tailorable and complex detection of thaw events. For example, an NFC tag method can tell a recipient that an item has thawed, whereas employment of many color change detectors within a package can be used to determine a degree to which this may or may not be a problem.

[0263] In some implementations, a melting point of a sample of saline solution can be controlled between 0°C and -20°C, and with some formulation work can be extended to below - 70°C (e.g., by using ethanol / water mixtures or a potassium formate solutions). A single sample of frozen saline can cause a change in a water sensitive hologram or other sensor on melting. In some implementations, a small volume of frozen material can be used to increase a response time or temperature sensitivity for sensing a temperature change. A fully recyclable or compostable material can be chosen for a well plate matrix sensor for temperature sensing or authenticity tracking.

[0264] Moreover, different sensing techniques can be used, in combination, to form a sensor. For example, upon detection of a color change on the surface of a package, a magnetic or NFC method, as described, can be used to determine a depth to which thawing may have occurred. One may also combine an output of a QR code revealed by thawing with, for example, information stored in an NFC device. In general, a collection of one or more thaw detection processes can be used within a system for temperature sensing or authenticity tracking.

[0265] Overview of Low Melting Point Solvents for Thaw Detection

[0266] Many organic solvents are stable and in small volumes essentially harmless to use in thawing detection. The precise use of such solvents can depend on which are chosen, but (for example) gratings can be produced in waxes by molding against open gratings, and a colored reflection from such gratings can be lost immediately upon exceeding a melting point of wax.

[0267] Alternatively, solvation of dyes can be employed to detect thawing of a solvent within a clear capped well. Some examples of low melting point solvents are shown in Table 2: Solvent Melting PointPCT Patent Application Attorney Docket No. 57274-0010WO1 Pentan-2-ol -72°C °

[0268] Shaped Ice and Ice Masking to Produce Thaw Sensors

[0269] A frozen solution with known chemical properties will begin to thaw at an experimentally determinable temperature. Therefore, aqueous (and other solvent)-based ices can be manufactured with almost any desired freezing point. This means that an ice can be selected to freeze or thaw at desired temperatures. Rapid freezing techniques can safely be applied to a solution to create thaw sensors based upon thawing of a shaped piece of ice at or above a desired temperature. The ice can be frozen in different forms (e.g., block or thin film) or in complex shapes.

[0270] By incorporating soluble dyes or pigments the ice can be made colored or opaque. Incorporation of the soluble dyes or pigments can affect a freezing point of the solution, so properties and / or concentrations of the soluble dyes or pigments must be taken into account if used.

[0271] Thawing of the ice can also be used to create different effects in a thaw sensor. For example, thawing of the ice can result in a change of color, an appearance of a visual indication (such as, a print or pattern)), and / or a change of shape. As an example, with respect to a change of shape, if the ice is frozen in a particular shape (e.g., a star, a heart, or a check / tick mark), and the ice is visible under a plastic film, then the loss of the visible frozen shape is indicative of a thaw event, and provides a simple visible indication that the thaw event has occurred.PCT Patent Application Attorney Docket No. 57274-0010WO1

[0272] Turning to FIG. 14A, FIG. 14A illustrates an individual component layout of a sponge sensor 1400a for thaw event detection, according to an implementation of the present disclosure.

[0273] In FIG. 14A, the sponge sensor 1400a includes a layer of saline ice 1402a and a sponge layer 1404a. In some implementations, the layer of saline ice 1402a may initially be shaped or flat. As illustrated, the layer of saline ice 1402a includes a green dyed, saline-based check mark 1406a that is frozen first and then frozen into the block of saline ice 1402a. The block of saline ice 1402a can be somewhat opaque.

[0274] The sponge layer 1404a can include a red printed cross / ’X’ 1408a on an upper surface of the sponge layer 1404a. In some implementations, sponges used can be natural, manufactured from biological materials (such as, cellulose), or made from polyurethane (or another foamed plastic). The sponge sensor 1400a is not restricted to materials regularly thought of as sponges, and the exploitation of materials that are simply spongy (absorbent) can be used to achieve a similar outcome. For example, freeze-dried fruit (e.g., apples or peaches), vegetables (e.g., courgetti / zucchini and luffa / loofah), fungus (e.g., mushrooms), processed food products (e.g., tofu), and grains (e.g., rolled oats or rice) can be used to absorb water, turning the sponge sensor into an entirely food-safe, edible material that can be employed in close proximity to food products inside food packaging. Moreover, low-cost, and biodegradable options (e.g., carboard, cellulose fibers, cotton wool, and similar materials) can also be used, and in some cases absorption of a thawed fluid can be achieved when the sponge sensor 1400a concept is used with pre-existing food product packaging. For example, a layer of ice can be adhered directly to package cardboard, a thicker bit of cardboard in part of the package, or to an added sponge / spongy material.

[0275] FIG.14B illustrates a sponge sensor 1400b formed by combining elements of FIG. 14A and in use, according to an implementation of the present disclosure.

[0276] In FIG.14B, the layer of saline ice 1402a (with the green dyed, saline-based check mark 1406a) is frozen to the sponge layer 1404a. As long as the saline layer 1402a remains frozen, the green dyed, saline-based check mark 1406a is visible and indicates that a thaw event has not occurred. If the saline ice 1402a melts, the red printed cross / ’X’ 1408a on an upper surface of the sponge 1404a becomes visible, indicating that a thaw event has occurred.

[0277] In another implementation, materials used to collect the solution from thawed ice may also incorporate soluble colored materials, such as edible food colorings, so that when the icePCT Patent Application Attorney Docket No. 57274-0010WO1 thaws, a visible color shift occurs (a previously invisible bright color) indicting that thawing has occurred. For example, a white-star-shaped piece of ice may, upon thawing, produce a bright red color by solubilizing a red food coloring and mobilizing it across sponge the white-star-shaped piece of ice was deposited upon with non-solubilized red food coloring.

[0278] Turning to FIG. 15A, FIG. 15A illustrates a chamber-type sensor 1500a for thaw determination, according to an implementation of the present disclosure. The sensor 1500a is frozen in an upside down orientation.

[0279] In FIG. 15A, a chamber 1502a can be used to hold thawed or re-frozen saline solution 1504a that is funneled into the chamber using a sloped inner surface (i.e., a simple funnel) 1506a. Vents 1508a are also configured into the chamber-type sensor both in the chamber and before the sloped inner surface. The vents permit air expansion / contraction based on temperature changes so as to not interfere with the flow of saline into the chamber if the temperature rises above a melting point of the frozen saline solution.

[0280] As illustrated in FIG.15A, on creation the chamber-type sensor is inverted to allow the saline solution to freeze at the functional top of the chamber-type sensor. In some implementations, the saline solution can be frozen in a sheet or shaped form. The chamber-type sensor is then turned over for use and attached to a frozen package.

[0281] FIG.15B illustrates a chamber-type sensor 1500b for thaw determination which is an inverted sensor of FIG.15A, according to an implementation of the present disclosure.

[0282] In FIG.15B, the frozen saline solution 1504a above the sloped inner surface 1506a obscures the interior of the chamber-type sensor 1502a. In some implementations, the upper surface 1502b of the sloped inner surface 1506a can be printed with a visible indicator of some type (e.g., a QR code, pattern, or other indicator) that is visible from the top of the chamber type sensor 1502a if the frozen saline solution 1504a thaws.

[0283] FIG.15C illustrates a chamber-type sensor 1500c for thaw determination after the frozen saline solution of FIG.15B has thawed due to a thaw event, according to an implementation of the present disclosure.

[0284] In FIG.15C, the frozen saline solution 1504a (at the top of the chamber-type sensor 1502a in FIG.15B) has thawed and collected (and possibly refrozen) in the chamber at the bottom of the chamber-type sensor 1502a, indicating a thaw event has occurred. Since the frozen saline 1504a solution above the sloped inner surface no longer obscures the interior of the chamber-typePCT Patent Application Attorney Docket No. 57274-0010WO1 sensor, the upper surface 1502b of the sloped inner surface 1506a is made visible from above the chamber-type sensor 1502a. In this configuration, a visible indicator of some type (e.g., a QR code, pattern, or other indicator) that is printed on the upper surface 1502b of the sloped inner surface 1506a can be viewed.

[0285] Turning for FIG. 16A, FIG. 16A illustrates a thaw detection sensor 1600a with simple object embedded in ice that cannot be seen or accessed until the ice thaws, according to an implementation of the present disclosure.

[0286] In FIG.16A, a small box shaped indicator (the simple object) 1602a is embedded in and hidden by a larger amount of saline ice 1604a. and indicates a thawing event has not occurred Similarly, by incorporating other simple objects (e.g., a plastic strip with a QR code on it, a figure logo, or 3D printed item) that cannot be seen or felt while the ice is frozen, there is an indication that a thawing event has not occurred.

[0287] FIG.16B illustrates a thawed thaw detection sensor 1600b after saline ice in FIG. 16A has melted, according to an implementation of the present disclosure.

[0288] In FIG.16B, the small box shaped indicator (the simple object) 1602a in FIG.16A is no longer embedded in and hidden by a larger amount of saline ice 1604a. As the larger amount of saline ice 1604a has thawed, it can be determined that a thaw event has occurred.

[0289] In some implementations, the direct thawing of ice, creating a melted aqueous solution, can also be exploited to dissolve and mobilize dye reactions, indicators, and substances they detect (e.g., a soluble acid solid and a power of Hydrogen (pH) indicator material). Alternatively, the direct thawing of ice can be utilized to create changes in another material. In one implementation, a compressed sponge, used independently of, or as part of a consumer promotion, can be printed with an image (e.g., a warning or a logo) and employed to absorb the water from melted ice. As the compressed sponge absorbs the water, the sponge expands and the image becomes visible.

[0290] Turning to FIG.17A, FIG.17A illustrates a frozen thaw sensor 1700a created with saline ice and a compressed sponge with a hidden image, according to an implementation of the present disclosure.

[0291] In FIG. 17A, the hidden image (not illustrated) is printed on the top of the compressed sponge 1702a, which is frozen to saline ice 1704a. As long as the saline ice 1704aPCT Patent Application Attorney Docket No. 57274-0010WO1 remains frozen, the compressed sponge 1702a will remain compressed and indicates that a thaw event has not occurred.

[0292] FIG.17B illustrates a thawed thaw sensor 1700b where the saline ice of FIG.17A has thawed and the compressed sponge has expanded to display the hidden image, according to an implementation of the present disclosure.

[0293] In FIG.17B, the compressed sponge 1702a has expanded after absorbing the water from the thawed saline ice 1704a and the hidden image (an ‘X’) 1702b made visible. The expanded compressed sponge 1702a with hidden image 1702b visible indicates that a thaw event has occurred.

[0294] In other implementations, hydrogels typically provide maximum expansion at lower temperatures and can respond to water from melting ice very quickly. In some implementations, the hydrogels may be used in planar form, as cubes, or as beads that expand upon exposure to liquid water; creating both a visual change (e.g., as large colored beads appearing behind a clear film), and a textual change (e.g., as bumpy surfaces are produced by swelling hydrogels). Hydrogels used for this application may be manufactured with natural materials (such as cellulose, starch, agarose, agar, chitin, chitosan, alginate, tragacanth gum, lignin, or any of a range of carbohydrates) or made from chemically created gels (such as, polyacrylic acid, polyacrylamide, or pHEMA). In some implementations, the hydrogels can be used as reservoirs used to collect thawed fluid or may be essential parts of a sensing apparatus (e.g., based on an appearance of color or texture shifts as previously described).

[0295] In another thaw sensor implementation, complex optical features (e.g., a grating structure with surface gratings) can be created at low-cost and in a broad range of materials (e.g., 3D printed bases with grating surfaces used to create holographic finishes and silicone and polyester molds (being appropriate for use with siloxanes, epoxies, etc.)). By selection of a clear material with a refractive index close to that of a solution that is frozen over the grating surface of the grating structure (e.g., approximately 1.3-1.4, which is the refractive index of saturated and near saturated saline solutions), the grating surface becomes invisible to the naked eye from the obverse side. Upon thawing of the solution, the grating surface becomes visible from the obverse side.

[0296] Turning to FIG.18A, FIG.18A illustrates an open grating structure of a thaw sensor 1800a with complex optical features, according to an implementation of the present disclosure.PCT Patent Application Attorney Docket No. 57274-0010WO1

[0297] In FIG.18A, the open grating structure (an ‘X’) 1802a faces upward and is visible.

[0298] FIG. 18B illustrates an open grating structure of a thaw sensor 1800b with a refractive index-matching-solution frozen to the upper surface of FIG. 18A, according to an implementation of the present disclosure.

[0299] In FIG.18B, the open grating structure (an ‘X’) 1802 is directly frozen to saline ice 1802b (the refractive index-matching-solution). With the refractive index-matching-solution 1802b frozen to the upper surface of the open grating structure (the ‘X’) 1802a, the open grating structure (the ‘X’) 1802a is not visible.

[0300] FIG.18C illustrates an inverted open grating structure of a thaw sensor 1800c with a refractive-index matching-solution frozen to the top surface of FIG. 18B, according to an implementation of the present disclosure.

[0301] In FIG. 18C, because the refractive index of the open grating structure (the ‘X’) 1802a is close to that of the refractive index-matching-solution 1802b, the open grating structure (the ‘X’) 1802a is also invisible from the obverse of the open grating structure (the ‘X’) 1802a.

[0302] FIG. 18D illustrates an open grating structure of a thaw sensor 1800d with a refractive index-matching-solution thawed from the top surface of FIG. 18C, according to an implementation of the present disclosure.

[0303] In FIG.18D, because the refractive-index-matching-solution 1802b has thawed, the open grating structure (the ‘X’) 1802a is visible from the obverse of the open grating structure 1802a.

[0304] In some implementations, water and saline ices can be exploited in a number of other complementary ways to determine whether a package has thawed. For example, creation of an electrical circuit that has embedded contacts on either side of a piece of ice that are brought together by a clip that closes when the ice melts. In an implementation, a thaw sensor component containing a battery and an LED light can be place on the outside of a package. A thaw event can be detected at any depth within a package, as long as electrical contacts can be accessed on the outside of the package to activate the battery and the LED light.

[0305] Turning to FIG.19A, FIG.19A illustrates a compressed spring thaw sensor 1900a with a compressed spring, according to an implementation of the present disclosure.

[0306] In FIG.19A, a frozen solution (e.g., a saline solution) 1902a is frozen under a clear cover (or window) 1904a. A colored indicator 1906a is placed underneath the frozen solutionPCT Patent Application Attorney Docket No. 57274-0010WO1 1902a and held in place with a compressed spring 1908a. In this configuration, the colored indicator 1906a is not visible from the top of the compressed spring thaw sensor 1900a through the clear cover 1904a.

[0307] FIG.19B illustrates a compressed spring thaw sensor 1900b with the compressed spring in FIG.19A in an expanded state, according to an implementation of the present disclosure.

[0308] In FIG.19B, once the frozen solution 1902a thaws, an aqueous solution from the frozen solution 1902a collects at the bottom (and is possibly re-frozen) of the compressed spring thaw sensor 1900b and the compressed spring 1908a expands as an expanded spring 1902b and pushes the colored indicator 1906a to the top of the compressed spring thaw sensor 1900b, where the colored indicator 1906a becomes visible through the clear cover 1904a. The colored indictor 1906a becoming visible indicates that a thaw event has occurred.

[0309] In some implementations, a compressed spring thaw sensor may be multiplexed with an integrated NFC sensor, which can be placed on top of the spring. The thawing of the frozen solution would bring the NFC sensor within range of a mobile computing device outside of the compressed spring thaw sensor. In some implementations, a QR code, barcode, or pattern may be included on top of the colored indicator to provide additional data or information.

[0310] Other implementations of thaw sensors can involve solutions frozen in syringes or small balloons, both stoppered before freezing. When the stoppers are removed, such that when packaged, the thawing of the solutions causes it to be squeezed into a package or to be deposited on any of the previously described spongy materials or even made visible by deposition into another container. In an implementation, a solution can be frozen in a small container that is inverted in final use, with a sponge or another container beneath it.

[0311] In yet another implementation of the previously mentioned small balloons, a thaw sensor can be created by placing a small, sealed balloon of saline solution in a shaped container during freezing, such that when the saline solution thaws the balloon reverts to being round. In a particular example, a small balloon is filled with saline solution and placed in a star-shaped (or any other shaped) mold, frozen, and placed under plastic wrap of a package for supply chain distribution. If, upon arrival of the package at its final supply chain destination, the balloon is no longer star shaped, but is instead presents as a round shape, it is an indication that the package has been stored above a thaw point of the particular concentration of saline solution. In some implementations, balloons can be used that are a range of colors, with each color corresponding toPCT Patent Application Attorney Docket No. 57274-0010WO1 a specific thaw temperature of contained saline solution, or the balloons may be frozen in different shapes to indicate a maximum temperature at which the package has been stored.

[0312] Turning to FIG.20, FIG.20 illustrates balloon thaw sensors 2000 filled with saline solution that are in different colors and frozen into different shapes, according to an implementation of the present disclosure.

[0313] In FIG.20, at (1), color coded balloons are filled with saline solution freezing at - 18°C, -10°C, and -4°C.

[0314] At (2), the balloons are frozen in star-shaped molds.

[0315] At (3), the frozen balloons are incorporated under a clear cover on packaging.

[0316] At (4), partial thaw above -10°C can be detected because the green and yellow balloons indicating thaw temperatures of -18°C and 10°C, respectively, are thawed and no longer in their star shapes.

[0317] At (5), a complete thaw above -4°C is indicated because all balloons are no longer in their star shapes.

[0318] It should be noted that the previously describe technique can be multiplexed. For example, multiple blocks of saline ices with different concentrations of salt can be produced, each a different shape, and thawing at different temperatures. They may be constructed such that each conveys a number directly relating to the maximum temperature reached, or such that each shape encodes a temperature point. For example, if differently shaped blocks of saline ice are engineered to have thaw points between -18°C and -4°C, then visual inspection of a package (or use of a mobile computing device software application programmed to recognize such shapes) would relay whether the package has been stored above (e.g., a pre-programmed temperature point) any chosen temperature.

[0319] Turning to FIG. 21, FIG. 21 illustrates an implementation of multiplexed, differently shaped thaw sensors 2100 of saline ices with varying thaw points between -18°C and - 4°C, according to an implementation of the present disclosure.

[0320] In FIG. 21, for example, if a temperature of -8°C is reached, the blue hexagon shaped thaw sensor 2102 can melt an ice layer associated with a freezing point of -10°C, leaving a hexagon-shaped yellow indictor 2104 indicating that a thaw event above -10°C occurred. Note that in this example, the blue square in 2106 and the blue ‘X’ 2108 below it would not display color change.PCT Patent Application Attorney Docket No. 57274-0010WO1

[0321] It should be noted that the selection of sensors, whether based on visible changes or parameters that can only be measured using a mobile computing device (e.g., a smartphone or other device), can be based on specific use-case scenarios. A choice of a visible sensor on or near the outer surface of a package, along with sensors providing more information as to the contents thereof, can be made to aid in a rational choice of how to handle the package. For example, the presence of a sensor indicating that thaw has occurred on the outside of a package may prompt a user to use a smartphone to access a sensor for specific temperature violations therein based on the thaw facilitated movement of an NFC tag or magnet therein. The purpose of multiplexing sensors can be for verification (e.g., multiple sensors of the same type to confirm a reading), to convey further information (e.g., a color based sensor alerting a user to a thaw such that they can access another sensor that contains more information, such as an NFC tag), for the determination of more complex thaw information (e.g., how long a package has been above a given temperature or the highest temperature to which it has been raised), and can be overt (e.g., with the arrangement and location of sensors being clearly apparent) or covert (e.g., with the location and arrangement of sensors being hidden or not apparent). The distinct advantages of each sensor type (e.g., color changes being very simple to use and very visible, NFC’s and magnetic sensors being ideal for determining thaw events within unopened packages, etc.) have use case scenarios both individually and in combination.

[0322] Package security and thermal integrity with respect to the interior and exterior of a package can be ensured through the use of one or more of the described implementations. For example, one or more of the previously described temperature / thaw detection sensors can be arranged on one or more surfaces of a package as well as in different zones of the interior / contents of the package. In this way, temperatures of all surfaces of the exterior of a package can be determined to ensure consistent storage temperature for an entire package. Similarly, multiple sensors on the interior of a package can be used to ensure that all zones of the interior of a package have maintained expected temperatures (e.g., the product itself may be packed with dry ice or other cooling means and be at a lower temperature than the surrounding packing material in a package itself). The sensors can indicate thermal condition of a package (and interior / contents) with respect to a temperature range from frozen, to chilled, and to un-chilled. By using multiple sensors, package security can also be ensured. For example, contents of a package can have multiple sensors applied in particular known positions or in a particular order. If it is discovered when thePCT Patent Application Attorney Docket No. 57274-0010WO1 package has been opened that sensor locations have been disturbed or that the sensors indicate unexpected temperatures, package security and / or thermal integrity can be questioned. Using one or more of the previously described sensors, color change, shape change, display of codes (e.g., QR codes and bar codes), RF signals, and / or other described indications can make determination of package security / thermal integrity efficient and obvious. Additionally, computer-based devices can be used to read / monitor a condition of sensors both on the exterior and in the interior of packages.

[0323] FIG. 22 is a block diagram illustrating an example of a computer-implemented System 2200 used to provide computational functionalities associated with described algorithms, methods, functions, processes, flows, and procedures, according to an implementation of the present disclosure. In the illustrated implementation, computer-implemented system 2200 includes a Computer 2202 and a Network 2230.

[0324] The illustrated Computer 2202 is intended to encompass any computing device, such as a server, desktop computer, laptop / notebook computer, wireless data port, smart phone, personal data assistant (PDA), tablet computer, one or more processors within these devices, or a combination of computing devices, including physical or virtual instances of the computing device, or a combination of physical or virtual instances of the computing device. Additionally, the Computer 2202 can include an input device, such as a keypad, keyboard, or touch screen, or a combination of input devices that can accept user information, and an output device that conveys information associated with the operation of the Computer 2202, including digital data, visual, audio, another type of information, or a combination of types of information, on a graphical-type user interface (UI) (or GUI) or other UI.

[0325] The Computer 2202 can serve in a role in a distributed computing system as, for example, a client, network component, a server, or a database or another persistency, or a combination of roles for performing the subject matter described in the present disclosure. The illustrated Computer 2202 is communicably coupled with a Network 2230. In some implementations, one or more components of the Computer 2202 can be configured to operate within an environment, or a combination of environments, including cloud-computing, local, or global.

[0326] At a high level, the Computer 2202 is an electronic computing device operable to receive, transmit, process, store, or manage data and information associated with the describedPCT Patent Application Attorney Docket No. 57274-0010WO1 subject matter. According to some implementations, the Computer 2202 can also include or be communicably coupled with a server, such as an application server, e-mail server, web server, caching server, or streaming data server, or a combination of servers.

[0327] The Computer 2202 can receive requests over Network 2230 (for example, from a client software application executing on another Computer 2202) and respond to the received requests by processing the received requests using a software application or a combination of software applications. In addition, requests can also be sent to the Computer 2202 from internal users (for example, from a command console or by another internal access method), external or third-parties, or other entities, individuals, systems, or computers.

[0328] Each of the components of the Computer 2202 can communicate using a System Bus 2203. In some implementations, any or all of the components of the Computer 2202, including hardware, software, or a combination of hardware and software, can interface over the System Bus 2203 using an application programming interface (API) 2212, a Service Layer 2213, or a combination of the API 2212 and Service Layer 2213. The API 2212 can include specifications for routines, data structures, and object classes. The API 2212 can be either computer-language independent or dependent and refer to a complete interface, a single function, or even a set of APIs. The Service Layer 2213 provides software services to the Computer 2202 or other components (whether illustrated or not) that are communicably coupled to the Computer 2202. The functionality of the Computer 2202 can be accessible for all service consumers using the Service Layer 2213. Software services, such as those provided by the Service Layer 2213, provide reusable, defined functionalities through a defined interface. For example, the interface can be software written in a computing language (for example JAVA or C++) or a combination of computing languages, and providing data in a particular format (for example, extensible markup language (XML)) or a combination of formats. While illustrated as an integrated component of the Computer 2202, alternative implementations can illustrate the API 2212 or the Service Layer 2213 as stand-alone components in relation to other components of the Computer 2202 or other components (whether illustrated or not) that are communicably coupled to the Computer 2202. Moreover, any or all parts of the API 2212 or the Service Layer 2213 can be implemented as a child or a sub-module of another software module, enterprise application, or hardware module without departing from the scope of the present disclosure.

[0329] The Computer 2202 includes an Interface 2204. Although illustrated as a singlePCT Patent Application Attorney Docket No. 57274-0010WO1 Interface 2204, two or more Interfaces 2204 can be used according to particular needs, desires, or particular implementations of the Computer 2202. The Interface 2204 is used by the Computer 2202 for communicating with another computing system (whether illustrated or not) that is communicatively linked to the Network 2230 in a distributed environment. Generally, the Interface 2204 is operable to communicate with the Network 2230 and includes logic encoded in software, hardware, or a combination of software and hardware. More specifically, the Interface 2204 can include software supporting one or more communication protocols associated with communications such that the Network 2230 or hardware of Interface 2204 is operable to communicate physical signals within and outside of the illustrated Computer 2202.

[0330] The Computer 2202 includes a Processor 2205. Although illustrated as a single Processor 2205, two or more Processors 2205 can be used according to particular needs, desires, or particular implementations of the Computer 2202. Generally, the Processor 2205 executes instructions and manipulates data to perform the operations of the Computer 2202 and any algorithms, methods, functions, processes, flows, and procedures as described in the present disclosure.

[0331] The Computer 2202 also includes a Database 2206 that can hold data for the Computer 2202, another component communicatively linked to the Network 2230 (whether illustrated or not), or a combination of the Computer 2202 and another component. For example, Database 2206 can be an in-memory or conventional database storing data consistent with the present disclosure. In some implementations, Database 2206 can be a combination of two or more different database types (for example, a hybrid in-memory and conventional database) according to particular needs, desires, or particular implementations of the Computer 2202 and the described functionality. Although illustrated as a single Database 2206, two or more databases of similar or differing types can be used according to particular needs, desires, or particular implementations of the Computer 2202 and the described functionality. While Database 2206 is illustrated as an integral component of the Computer 2202, in alternative implementations, Database 2206 can be external to the Computer 2202. The Database 2206 can hold and operate on at least any data type mentioned or any data type consistent with this disclosure.

[0332] The Computer 2202 also includes a Memory 2207 that can hold data for the Computer 2202, another component or components communicatively linked to the Network 2230 (whether illustrated or not), or a combination of the Computer 2202 and another component.PCT Patent Application Attorney Docket No. 57274-0010WO1 Memory 2207 can store any data consistent with the present disclosure. In some implementations, Memory 2207 can be a combination of two or more different types of memory (for example, a combination of semiconductor and magnetic storage) according to particular needs, desires, or particular implementations of the Computer 2202 and the described functionality. Although illustrated as a single Memory 2207, two or more Memories 2207 or similar or differing types can be used according to particular needs, desires, or particular implementations of the Computer 2202 and the described functionality. While Memory 2207 is illustrated as an integral component of the Computer 2202, in alternative implementations, Memory 2207 can be external to the Computer 2202.

[0333] The Application 2208 is an algorithmic software engine providing functionality according to particular needs, desires, or particular implementations of the Computer 2202, particularly with respect to functionality described in the present disclosure. For example, Application 2208 can serve as one or more components, modules, or applications. Further, although illustrated as a single Application 2208, the Application 2208 can be implemented as multiple Applications 2208 on the Computer 2202. In addition, although illustrated as integral to the Computer 2202, in alternative implementations, the Application 2208 can be external to the Computer 2202.

[0334] The Computer 2202 can also include a Power Supply 2214. The Power Supply 2214 can include a rechargeable or non-rechargeable battery that can be configured to be either user- or non-user-replaceable. In some implementations, the Power Supply 2214 can include power- conversion or management circuits (including recharging, standby, or another power management functionality). In some implementations, the Power Supply 2214 can include a power plug to allow the Computer 2202 to be plugged into a wall socket or another power source to, for example, power the Computer 2202 or recharge a rechargeable battery.

[0335] There can be any number of Computers 2202 associated with, or external to, a computer system containing Computer 2202, each Computer 2202 communicating over Network 2230. Further, the term “client,” “user,” or other appropriate terminology can be used interchangeably, as appropriate, without departing from the scope of the present disclosure. Moreover, the present disclosure contemplates that many users can use one Computer 2202, or that one user can use multiple computers 2202.PCT Patent Application Attorney Docket No. 57274-0010WO1

[0336] FIG. 23 is a flowchart illustrating an example of a method 2300 for temperature detection, according to an implementation of the present disclosure. For clarity of presentation, the description that follows generally describes method 2300 in the context of the other figures in this description. In some implementations, various steps of method 2300 can be run in parallel, in combination, in loops, or in any order.

[0337] At 2302, . providing a sensor capable of changing a color characteristic responsive to an altered temperature is provided. In some implementations, the sensor includes a saline solution. In some implementations, the sensor includes a dyeable material. In some implementations, the sensor includes a dye. In some implementations, the dye is mixed with the dyeable material in a frozen state to form a frozen mixture, and the frozen mixture is frozen to volume of frozen saline solution. In some implementations, the dyeable material is mixed with the dye and frozen to a volume of frozen saline solution. In some implementations, the altered temperature causes the volume of frozen saline solution to thaw and diffuse the dye into the dyeable material. In some implementations, the dye is injected into the dyeable material and the dyeable material is flash frozen to prevent diffusion of the dye into the dyeable material. Optionally, in some implementations, the sensor is covered with a waterproof material to prevent condensation of water droplets from an atmosphere from triggering a false positive thaw response. From 2302, method 2300 proceeds to 2304

[0338] At 2304, the sensor is attached to a package such that, during shipment of the package, the altered temperature can cause the color characteristic of the sensor to change. In some implementations, the dye changes color when hydrated by thawed saline solution. In some implementations, the dye is a transition metal salt that changes color when hydrated by thawed saline solution. From 2304, method 2300 proceeds to 2306.

[0339] At 2306, a color state of the sensor following the altered temperature is analyzed. After 2306, method 2300 can stop.

[0340] Described implementations of the subject matter can include one or more features, alone or in combination.

[0341] For example, in a first implementation, a solution-based temperature detection device, comprising: a saline pocket; a saline solution contained within the saline pocket; and a textured surface contained within the saline pocket.PCT Patent Application Attorney Docket No. 57274-0010WO1

[0342] The foregoing and other described implementations can each, optionally, include one or more of the following features:

[0343] A first feature, combinable with any of the following features, wherein a freezing point of the saline solution can be tailored using a concentration of saline solution or by addition of formats to the saline solution.

[0344] A second feature, combinable with any of the previous or following features, wherein the textured surface contained within the saline pocket is ridged.

[0345] A third feature, combinable with any of the previous or following features, wherein the textured surface contained within the saline pocket is ridged.

[0346] A fourth feature, combinable with any of the previous or following features, wherein the saline solution is frozen, as a frozen saline solution, to the textured surface while in an inverted position.

[0347] A fifth feature, combinable with any of the previous or following features, wherein, when oriented in an upright position, the frozen saline solution obfuscates the textured surface and / or creates a tactilely smooth surface.

[0348] A sixth feature, combinable with any of the previous or following features, wherein a surface of the saline pocket opposite the textured surface is adhered to an object.

[0349] A seventh feature, combinable with any of the previous or following features, comprising a hollow portion of the saline pocket opposite to the textured surface to permit thawed saline solution to pool.

[0350] An eighth feature, combinable with any of the previous or following features, wherein the textured surface is hollow to permit thawed saline solution to pool within the textured surface.

[0351] For example, in a second implementation, a method for temperature detection, comprises: providing a sensor capable of changing a color characteristic responsive to an altered temperature; attaching the sensor to a package such that, during shipment of the package, the altered temperature can cause the color characteristic of the sensor to change; and analyzing a color state of the sensor following the altered temperature.

[0352] The foregoing and other described implementations can each, optionally, include one or more of the following features:PCT Patent Application Attorney Docket No. 57274-0010WO1

[0353] A first feature, combinable with any of the following features, wherein the sensor comprises a saline solution.

[0354] A second feature, combinable with any of the previous or following features, wherein the sensor comprises a dyeable material.

[0355] A third feature, combinable with any of the previous or following features, wherein the sensor comprises a dye.

[0356] A fourth feature, combinable with any of the previous or following features, wherein the dye is mixed with the dyeable material in a frozen state to form a frozen mixture, and the frozen mixture is frozen to a volume of frozen saline solution.

[0357] A fifth feature, combinable with any of the previous or following features, wherein the dyeable material is mixed with the dye and frozen to a volume of frozen saline solution.

[0358] A sixth feature, combinable with any of the previous or following features, wherein the altered temperature causes the volume of frozen saline solution to thaw and diffuse the dye into the dyeable material.

[0359] A seventh feature, combinable with any of the previous or following features, wherein the dye is injected into the dyeable material and the dyeable material is flash frozen to prevent diffusion of the dye into the dyeable material.

[0360] An eighth feature, combinable with any of the previous or following features, comprising: covering the sensor with a waterproof material to prevent condensation of water droplets from an atmosphere from triggering a false positive thaw response.

[0361] A ninth feature, combinable with any of the previous or following features, wherein the dye changes color when hydrated by thawed saline solution.

[0362] A tenth feature, combinable with any of the previous or following features, wherein the dye is a transition metal salt that changes color when hydrated by thawed saline solution.

[0363] For example, in a third implementation, a temperature detection device, comprises: at least one hydrochromic paint; a volume of ice; and a surface in contact with the volume of ice and painted with the at least one hydrochromic paint.

[0364] The foregoing and other described implementations can each, optionally, include one or more of the following features:

[0365] A first feature, combinable with any of the following features, wherein, when the volume of ice melts the at least one hydrochromic paint changes color or becomes clear.PCT Patent Application Attorney Docket No. 57274-0010WO1

[0366] A second feature, combinable with any of the previous or following features, wherein the at least one hydrochromic paint is used to paint a pattern, word, security code, quick response (QR) code, or bar code.

[0367] For example, in a fourth implementation, a temperature detection device, comprises: a volume of ice; and a power of hydrogen (pH) sensitive or enzyme sensitive indicator, wherein the pH sensitive indicator detects a pH of a thawed volume of ice.

[0368] The foregoing and other described implementations can each, optionally, include one or more of the following features:

[0369] A first feature, combinable with any of the following features, wherein the pH sensitive indicator changes color when detecting a pH of the thawed volume of ice.

[0370] For example, in a fifth implementation, a temperature detection device, comprising: a volume of solution; and an enzyme sensitive indicator, wherein the enzyme sensitive indicator detects an enzymatic reaction that occurs when the solution freezes.

[0371] The foregoing and other described implementations can each, optionally, include one or more of the following features:

[0372] A first feature, combinable with any of the following features, wherein the enzyme sensitive indicator changes color when detecting the enzymatic reaction that occurs when the solution freezes.

[0373] For example, in a sixth implementation, a temperature detection device, comprises: an open grating structure; and a volume of refractive index-matching-solution frozen to the open grating structure rendering the open grating structure invisible.

[0374] The foregoing and other described implementations can each, optionally, include one or more of the following features:

[0375] A first feature, combinable with any of the following features, wherein the volume of refractive index-matching-solution frozen to the open grating structure is adhered to an item.

[0376] A second feature, combinable with any of the previous or following features, wherein the open grating structure becomes visible upon thaw of the volume of refractive index- matching-solution frozen to the open grating structure.

[0377] For example, in a seventh implementation, a temperature detection device, comprises: an open grating structure or a Denisyuk hologram comprised of meltable or water- soluble material.PCT Patent Application Attorney Docket No. 57274-0010WO1

[0378] The foregoing and other described implementations can each, optionally, include one or more of the following features:

[0379] A first feature, combinable with any of the following features, wherein a color change occurs with the open grating structure or a Denisyuk hologram when melting or solubilizing.

[0380] For example, in an eighth implementation, a temperature detection device, comprises: a solution covered by a thin film and frozen, as a frozen solution, in a shape of a mold, wherein on thawing, the frozen solution changes shape to indicate a thaw event has occurred.

[0381] For example, in a tenth implementation, a temperature detection device, comprises: multiple wells in a matrix pattern, wherein each well of the multiple wells comprises a sensor and a frozen solution with different properties than frozen solution in other wells of the multiple wells, and wherein the sensor in each well of the multiple wells are used to determine both a highest temperature reached and a time the temperature detection device has been at or above the highest temperature reached.

[0382] The foregoing and other described implementations can each, optionally, include one or more of the following features:

[0383] A first feature, combinable with any of the following features, wherein the multiple wells can be arranged to provide covert data.

[0384] A second feature, combinable with any of the previous or following features, wherein the sensor in each well of the multiple wells can be read by a mobile computing device.

[0385] Implementations of the subject matter and the functional operations described in this specification can be implemented in digital electronic circuitry, in tangibly embodied computer software or firmware, in computer hardware, including the structures disclosed in this specification and their structural equivalents, or in combinations of one or more of them. Software implementations of the described subject matter can be implemented as one or more computer programs, that is, one or more modules of computer program instructions encoded on a tangible, non-transitory, computer-readable medium for execution by, or to control the operation of, a computer or computer-implemented system. Alternatively, or additionally, the program instructions can be encoded in / on an artificially generated propagated signal, for example, a machine-generated electrical, optical, or electromagnetic signal that is generated to encode information for transmission to a receiver apparatus for execution by a computer or computer-PCT Patent Application Attorney Docket No. 57274-0010WO1 implemented system. The computer-storage medium can be a machine-readable storage device, a machine-readable storage substrate, a random or serial access memory device, or a combination of computer-storage mediums. Configuring one or more computers means that the one or more computers have installed hardware, firmware, or software (or combinations of hardware, firmware, and software) so that when the software is executed by the one or more computers, particular computing operations are performed. The computer storage medium is not, however, a propagated signal.

[0386] The term “real-time,” “real time,” “realtime,” “real (fast) time (RFT),” “near(ly) real-time (NRT),” “quasi real-time,” or similar terms (as understood by one of ordinary skill in the art), means that an action and a response are temporally proximate such that an individual perceives the action and the response occurring substantially simultaneously. For example, the time difference for a response to display (or for an initiation of a display) of data following the individual’s action to access the data can be less than 1 millisecond (ms), less than 1 second (s), or less than 5 s. While the requested data need not be displayed (or initiated for display) instantaneously, it is displayed (or initiated for display) without any intentional delay, taking into account processing limitations of a described computing system and time required to, for example, gather, accurately measure, analyze, process, store, or transmit the data.

[0387] The terms “data processing apparatus,” “computer,” “computing device,” or “electronic computer device” (or an equivalent term as understood by one of ordinary skill in the art) refer to data processing hardware and encompass all kinds of apparatuses, devices, and machines for processing data, including by way of example, a programmable processor, a computer, or multiple processors or computers. The computer can also be, or further include special-purpose logic circuitry, for example, a central processing unit (CPU), a field- programmable gate array (FPGA), or an application-specific integrated circuit (ASIC). In some implementations, the computer or computer-implemented system or special-purpose logic circuitry (or a combination of the computer or computer-implemented system and special-purpose logic circuitry) can be hardware- or software-based (or a combination of both hardware- and software-based). The computer can optionally include code that creates an execution environment for computer programs, for example, code that constitutes processor firmware, a protocol stack, a database management system, an operating system, or a combination of execution environments. The present disclosure contemplates the use of a computer or computer-implemented system withPCT Patent Application Attorney Docket No. 57274-0010WO1 an operating system, for example LINUX, UNIX, WINDOWS, MAC OS, ANDROID, or IOS, or a combination of operating systems.

[0388] A computer program, which can also be referred to or described as a program, software, a software application, a unit, a module, a software module, a script, code, or other component can be written in any form of programming language, including compiled or interpreted languages, or declarative or procedural languages, and it can be deployed in any form, including, for example, as a stand-alone program, module, component, or subroutine, for use in a computing environment. A computer program can, but need not, correspond to a file in a file system. A program can be stored in a portion of a file that holds other programs or data, for example, one or more scripts stored in a markup language document, in a single file dedicated to the program in question, or in multiple coordinated files, for example, files that store one or more modules, sub-programs, or portions of code. A computer program can be deployed to be executed on one computer or on multiple computers that are located at one site or distributed across multiple sites and interconnected by a communication network.

[0389] While portions of the programs illustrated in the various figures can be illustrated as individual components, such as units or modules, that implement described features and functionality using various objects, methods, or other processes, the programs can instead include a number of sub-units, sub-modules, third-party services, components, libraries, and other components, as appropriate. Conversely, the features and functionality of various components can be combined into single components, as appropriate. Thresholds used to make computational determinations can be statically, dynamically, or both statically and dynamically determined.

[0390] Described methods, processes, or logic flows represent one or more examples of functionality consistent with the present disclosure and are not intended to limit the disclosure to the described or illustrated implementations, but to be accorded the widest scope consistent with described principles and features. The described methods, processes, or logic flows can be performed by one or more programmable computers executing one or more computer programs to perform functions by operating on input data and generating output data. The methods, processes, or logic flows can also be performed by, and computers can also be implemented as, special- purpose logic circuitry, for example, a CPU, an FPGA, or an ASIC.

[0391] Computers for the execution of a computer program can be based on general or special-purpose microprocessors, both, or another type of CPU. Generally, a CPU can receivePCT Patent Application Attorney Docket No. 57274-0010WO1 instructions and data from and write to a memory. The essential elements of a computer are a CPU, for performing or executing instructions, and one or more memory devices for storing instructions and data. Generally, a computer can also include, or be operatively coupled to, receive data from or transfer data to, or both, one or more mass storage devices for storing data, for example, magnetic, magneto-optical disks, or optical disks. However, a computer need not have such devices. Moreover, a computer can be embedded in another device, for example, a mobile telephone, a personal digital assistant (PDA), a mobile audio or video player, a game console, a global positioning system (GPS) receiver, or a portable memory storage device, for example, a universal serial bus (USB) flash drive, to name just a few.

[0392] Non-transitory computer-readable media for storing computer program instructions and data can include all forms of permanent / non-permanent or volatile / non-volatile memory, media and memory devices, including by way of example semiconductor memory devices, for example, random access memory (RAM), read-only memory (ROM), phase change memory (PRAM), static random access memory (SRAM), dynamic random access memory (DRAM), erasable programmable read-only memory (EPROM), electrically erasable programmable read- only memory (EEPROM), and flash memory devices; magnetic devices, for example, tape, cartridges, cassettes, internal / removable disks; magneto-optical disks; and optical memory devices, for example, digital versatile / video disc (DVD), compact disc (CD)-ROM, DVD+ / -R, DVD-RAM, DVD-ROM, high-definition / density (HD)-DVD, and BLU-RAY / BLU-RAY DISC (BD), and other optical memory technologies. The memory can store various objects or data, including caches, classes, frameworks, applications, modules, backup data, jobs, web pages, web page templates, data structures, database tables, repositories storing dynamic information, or other appropriate information including any parameters, variables, algorithms, instructions, rules, constraints, or references. Additionally, the memory can include other appropriate data, such as logs, policies, security or access data, or reporting files. The processor and the memory can be supplemented by, or incorporated in, special-purpose logic circuitry.

[0393] To provide for interaction with a user, implementations of the subject matter described in this specification can be implemented on a computer having a display device, for example, a cathode ray tube (CRT), liquid crystal display (LCD), light emitting diode (LED), or plasma monitor, for displaying information to the user and a keyboard and a pointing device, for example, a mouse, trackball, or trackpad by which the user can provide input to the computer.PCT Patent Application Attorney Docket No. 57274-0010WO1 Input can also be provided to the computer using a touchscreen, such as a tablet computer surface with pressure sensitivity or a multi-touch screen using capacitive or electric sensing. Other types of devices can be used to interact with the user. For example, feedback provided to the user can be any form of sensory feedback (such as, visual, auditory, tactile, or a combination of feedback types). Input from the user can be received in any form, including acoustic, speech, or tactile input. In addition, a computer can interact with the user by sending documents to and receiving documents from a client computing device that is used by the user (for example, by sending web pages to a web browser on a user’s mobile computing device in response to requests received from the web browser).

[0394] The term “graphical user interface (GUI) can be used in the singular or the plural to describe one or more graphical user interfaces and each of the displays of a particular graphical user interface. Therefore, a GUI can represent any graphical user interface, including but not limited to, a web browser, a touch screen, or a command line interface (CLI) that processes information and efficiently presents the information results to the user. In general, a GUI can include a number of user interface (UI) elements, some or all associated with a web browser, such as interactive fields, pull-down lists, and buttons. These and other UI elements can be related to or represent the functions of the web browser.

[0395] Implementations of the subject matter described in this specification can be implemented in a computing system that includes a back-end component, for example, as a data server, or that includes a middleware component, for example, an application server, or that includes a front-end component, for example, a client computer having a graphical user interface or a Web browser through which a user can interact with an implementation of the subject matter described in this specification, or any combination of one or more such back-end, middleware, or front-end components. The components of the system can be interconnected by any form or medium of wireline or wireless digital data communication (or a combination of data communication), for example, a communication network. Examples of communication networks include a local area network (LAN), a radio access network (RAN), a metropolitan area network (MAN), a wide area network (WAN), Worldwide Interoperability for Microwave Access (WIMAX), a wireless local area network (WLAN) using, for example, 802.11x or other protocols, all or a portion of the Internet, another communication network, or a combination of communication networks. The communication network can communicate with, for example,PCT Patent Application Attorney Docket No. 57274-0010WO1 Internet Protocol (IP) packets, frame relay frames, Asynchronous Transfer Mode (ATM) cells, voice, video, data, or other information between network nodes.

[0396] The computing system can include clients and servers. A client and server are generally remote from each other and typically interact through a communication network. The relationship of client and server arises by virtue of computer programs running on the respective computers and having a client-server relationship to each other.

[0397] While this specification contains many particular implementation details, these should not be construed as limitations on the scope of any inventive concept or on the scope of what can be claimed, but rather as descriptions of features that can be specific to particular implementations of particular inventive concepts. Certain features that are described in this specification in the context of separate implementations can also be implemented, in combination, in a single implementation. Conversely, various features that are described in the context of a single implementation can also be implemented in multiple implementations, separately, or in any sub-combination. Moreover, although previously described features can be described as acting in certain combinations and even initially claimed as such, one or more features from a claimed combination can, in some implementations, be excised from the combination, and the claimed combination can be directed to a sub-combination or variation of a sub-combination.

[0398] Particular implementations of the subject matter have been described. Other implementations, alterations, and permutations of the described implementations are within the scope of the following claims as will be apparent to those skilled in the art. While operations, steps, or actions are depicted in the drawings or claims in a particular order, this should not be understood as requiring that such operations, steps, or actions be performed in the particular order shown or in sequential order, or that all illustrated operations, steps, or actions be performed (some operations, steps, or actions can be considered optional), to achieve desirable results. In certain circumstances, multitasking or parallel processing (or a combination of multitasking and parallel processing) can be advantageous and performed as deemed appropriate.

[0399] The separation or integration of various components and / or system modules in the previously described implementations should not be understood as requiring such separation or integration in all implementations. In some implementations, described components and system modules can be integrated together in a single software product or packaged into multiple software products.PCT Patent Application Attorney Docket No. 57274-0010WO1

[0400] Accordingly, the previously described example implementations do not define or constrain the present disclosure. Other changes, substitutions, and alterations are also possible without departing from the scope of the present disclosure.

[0401] Furthermore, any claimed implementation may be applicable to a computer- implemented method; a non-transitory, computer-readable medium storing computer-readable instructions to perform the computer-implemented method; and / or a computer system comprising a computer memory interoperably coupled with a hardware processor configured to perform the computer-implemented method or the instructions stored on the non-transitory, computer-readable medium.

[0402] In view of the above-described implementations of subject matter this application discloses the following list of embodiments, wherein one feature of an embodiment in isolation or more than one feature of said embodiment taken in combination and, optionally, in combination with one or more features of one or more further embodiments are further embodiments also falling within the disclosure of this application.

[0403] Embodiment 1: A method comprising: providing a sensor capable of changing a color characteristic responsive to an altered temperature; generating a secure code dependent on the color characteristic of the sensor; and attaching the secure code to a package such that, during shipping of the package, the altered temperature can cause the color characteristic of the sensor to change, thereby rendering the secure code inoperable.

[0404] Embodiment 2: The method of any of the preceding embodiments, wherein the sensor is provided adjacent to a frozen volume such that, when the frozen volume thaws in response to the altered temperature, the sensor is exposed, wherein the sensor comprises at least one of: a colorimetric sensor or a hologram.

[0405] Embodiment 3: The method of any of the preceding embodiments, wherein the sensor comprises a colorimetric sensor that is enzyme sensitive.

[0406] Embodiment 4: The method of any of the preceding embodiments, wherein the changed color characteristic comprises one or more of: a presence or absence of a discernable color, a changed luminance level, or a change response to incident light of a given wavelength.

[0407] Embodiment 5: The method of any of the preceding embodiments, wherein the secure code encodes at least one of: a data of manufacturing, a place of manufacturing, an identity of the manufacturer, a date of shipping, or a temperature at packaging.PCT Patent Application Attorney Docket No. 57274-0010WO1

[0408] Embodiment 6: The method of any of the preceding embodiments, wherein the secure code comprises at least one of: a QR code, a bar code, or a covert code.

[0409] Embodiment 7: The method of any of the preceding embodiments, wherein the secure code is generated by including the sensor in the secure code, or by presenting the sensor alongside the secure code.

[0410] Embodiment 8: The method of any of the preceding embodiments, wherein attaching the secure code comprises at least one of: enclosing the secure code inside the package, printing the secure code on the package, and tagging the secure code outside the package.

[0411] Embodiment 9: The method of any of the preceding embodiments, wherein the package is a food product package.

[0412] Embodiment 10: One or more non-transitory computer storage media encoded with instructions that, when executed by one or more computers, cause the one or more computers to perform the method of any preceding claim.

[0413] Embodiment 11: A system comprising one or more computers and one or more storage devices on which are stored instructions that are operable, when executed by the one or more computers, to cause the one or more computers to perform the method of any of the preceding embodiments.

[0414] Embodiment 12: A method comprising: obtaining data from one or more sensors attached to a package, the one or more sensors including a temperature reading device; generating a data package that includes the data from the one or more sensors attached to the package; and transmitting the data package to a receiving system.

[0415] Embodiment 13: The method of the preceding embodiment, wherein the temperature reading device comprises a color changing element that indicates when a temperature threshold has been reached.

[0416] Embodiment 14: The method of any of the preceding embodiments, wherein obtaining the data from the one or more sensors attached to the package comprises: receiving signals from the one or more sensors, wherein the one or more sensors include near-field communication (NFC) systems configured to communicate using LoRa wireless modulation.

[0417] Embodiment 15: The method of any of the preceding embodiments, comprising: encrypting the data package prior to transmitting the encrypted data package to the receiving system.PCT Patent Application Attorney Docket No. 57274-0010WO1

[0418] Embodiment 16: One or more non-transitory computer storage media encoded with instructions that, when executed by one or more computers, cause the one or more computers to perform the method of any of the preceding embodiments.

[0419] Embodiment 17: A system comprising one or more computers and one or more storage devices on which are stored instructions that are operable, when executed by the one or more computers, to cause the one or more computers to perform the method of any of the preceding embodiments.

[0420] Embodiment 18: The method of the preceding embodiment, further comprising generating a biochemical change in response to a temperature change using biochemical or microbiological agents.

[0421] Embodiment 19: The method of any of the preceding embodiments, wherein biochemical or microbiological agents comprises enzymes or microbial cells.

[0422] Embodiment 20: The method of any of the preceding embodiments, wherein agents such as enzymes or microbial cells are utilized to generate a biochemical change in response to a temperature change, this being visualized or detected by a chemical color change or a change in turbidity.

[0423] Embodiment 21: The method of any of the preceding embodiments, further comprising edge computing using a mobile-device application.

[0424] Embodiment 22: The method of any of the preceding embodiments, wherein a smartphone includes the mobile-device application.

[0425] Embodiment 23: A method comprising: obtaining, using a reader, a signal from a secure code attached to a package, wherein the secure code comprises (i) a first portion indicating shipping information of the package and (ii) a second portion indicating quality information of the package; and determining, using the signal from the secure code, whether the package satisfies an authenticity or quality threshold.

[0426] Embodiment 24: The method of the preceding embodiment, wherein the signal from the secure code comprises an image of the secure code taken by a camera of the reader.

[0427] Embodiment 25: The method of any of the preceding embodiments, wherein the second portion of the secure code comprises a color changing element that indicates when a temperature threshold has been reached.

[0428] Embodiment 26: The method of any of the preceding embodiments, wherein thePCT Patent Application Attorney Docket No. 57274-0010WO1 signal from the secure code comprises a radio frequency signal.

[0429] Embodiment 27: The method of any of the preceding embodiments, wherein the reader comprises a smartphone.

[0430] Embodiment 28: One or more non-transitory computer storage media encoded with instructions that, when executed by one or more computers, cause the one or more computers to perform the method of any of the preceding embodiments.

[0431] Embodiment 29: A system comprising one or more computers and one or more storage devices on which are stored instructions that are operable, when executed by the one or more computers, to cause the one or more computers to perform the method of any of the preceding embodiments.

Claims

PCT Patent Application Attorney Docket No. 57274-0010WO1 CLAIMS What is claimed is:

1. A solution-based temperature detection device, comprising: a saline pocket; a saline solution contained within the saline pocket; and a textured surface contained within the saline pocket.

2. The solution-based temperature detection device of claim 1, wherein a freezing point of the saline solution can be tailored using a concentration of saline solution or by addition of formats to the saline solution.

3. The solution-based temperature detection device of claim 1, wherein the textured surface contained within the saline pocket is ridged.

4. The solution-based temperature detection device of claim 3, wherein the saline solution is frozen, as a frozen saline solution, to the textured surface while in an inverted position.

5. The solution-based temperature detection device of claim 4, wherein, when oriented in an upright position, the frozen saline solution obfuscates the textured surface and / or creates a tactilely smooth surface.

6. The solution-based temperature detection device of claim 1, wherein a surface of the saline pocket opposite the textured surface is adhered to an object.

7. The solution-based temperature detection device of claim 1, comprising a hollow portion of the saline pocket opposite to the textured surface to permit thawed saline solution to pool.

8. The solution-based temperature detection device of claim 1, wherein the textured surface is hollow to permit thawed saline solution to pool within the textured surface.PCT Patent Application Attorney Docket No. 57274-0010WO1 9. A method for temperature detection, comprising: providing a sensor capable of changing a color characteristic responsive to an altered temperature; attaching the sensor to a package such that, during shipment of the package, the altered temperature can cause the color characteristic of the sensor to change; and analyzing a color state of the sensor following the altered temperature.

10. The method for temperature detection of claim 9, wherein the sensor comprises a saline solution.

11. The method for temperature detection of claims 9-10, wherein the sensor comprises a dyeable material.

12. The method for temperature detection of claims 9-11, wherein the sensor comprises a dye.

13. The method for temperature detection of claims 10-12, wherein the dye is mixed with the dyeable material in a frozen state to form a frozen mixture, and the frozen mixture is frozen to a volume of frozen saline solution.

14. The method for temperature detection of claims 10-12, wherein the dyeable material is mixed with the dye and frozen to a volume of frozen saline solution.

15. The method for temperature detection of claims 13-14, wherein the altered temperature causes the volume of frozen saline solution to thaw and diffuse the dye into the dyeable material.

16. The method for temperature detection of claims 9 and 11-12, wherein the dye is injected into the dyeable material and the dyeable material is flash frozen to prevent diffusion of the dye into the dyeable material.

17. The method for temperature detection of claim 9 comprising:PCT Patent Application Attorney Docket No. 57274-0010WO1 covering the sensor with a waterproof material to prevent condensation of water droplets from an atmosphere from triggering a false positive thaw response.

18. The method for temperature detection of claims 10-12, wherein the dye changes color when hydrated by thawed saline solution.

19. The method for temperature detection of claims 9-10 and 12, wherein the dye is a transition metal salt that changes color when hydrated by thawed saline solution.

20. A temperature detection device, comprising: at least one hydrochromic paint; a volume of ice; and a surface in contact with the volume of ice and painted with the at least one hydrochromic paint.

21. The temperature detection device of claim 20, wherein, when the volume of ice melts the at least one hydrochromic paint changes color or becomes clear.

22. The temperature detection device of claim 20, wherein the at least one hydrochromic paint is used to paint a pattern, word, security code, quick response (QR) code, or bar code.

23. A temperature detection device, comprising: a volume of ice; and a power of hydrogen (pH) sensitive or enzyme sensitive indicator, wherein the pH sensitive indicator detects a pH of a thawed volume of ice.

24. The temperature detection device of claim 23, wherein the pH sensitive indicator changes color when detecting a pH of the thawed volume of ice.

25. A temperature detection device, comprising: a volume of solution; andPCT Patent Application Attorney Docket No. 57274-0010WO1 an enzyme sensitive indicator, wherein the enzyme sensitive indicator detects an enzymatic reaction that occurs when the solution freezes.

26. The temperature detection device of claim 25, wherein the enzyme sensitive indicator changes color when detecting the enzymatic reaction that occurs when the solution freezes.

27. A temperature detection device, comprising: an open grating structure; and a volume of refractive index-matching-solution frozen to the open grating structure rendering the open grating structure invisible.

28. The temperature detection device of claim 27, wherein the volume of refractive index- matching-solution frozen to the open grating structure is adhered to an item.

29. The temperature detection device of claim 28, wherein the open grating structure becomes visible upon thaw of the volume of refractive index-matching-solution frozen to the open grating structure.

30. A temperature detection device, comprising: an open grating structure or a Denisyuk hologram comprised of meltable or water-soluble material.

31. The temperature detection device of claim 30, wherein a color change occurs with the open grating structure or a Denisyuk hologram when melting or solubilizing.

32. A temperature detection device, comprising: a solution covered by a thin film and frozen, as a frozen solution, in a shape of a mold, wherein on thawing, the frozen solution changes shape to indicate a thaw event has occurred.

33. A temperature detection device, comprising:PCT Patent Application Attorney Docket No. 57274-0010WO1 multiple wells in a matrix pattern, wherein each well of the multiple wells comprises a sensor and a frozen solution with different properties than frozen solution in other wells of the multiple wells, and wherein the sensor in each well of the multiple wells are used to determine both a highest temperature reached and a time the temperature detection device has been at or above the highest temperature reached.

34. The temperature detection device of claim 33, wherein the multiple wells can be arranged to provide covert data.

35. The temperature detection device of claim 33, wherein the sensor in each well of the multiple wells can be read by a mobile computing device.2 / 23Hollow textured surface device, frozen inverted202 104FIG. 2AHollow textured surface, covered in frozen saline(no thaw detected)Hollow textured surface, covered in frozen saline 2 (thaw detected)FIG. 2C3 / 23Super-hydrophilic Rapid solubilisation / food dye particles capillary actionFIG. 34 / 23FIG. 4AFIG. 4B5 / 23FIG. 56 / 23FIG. 67 / 23FIG. 7B8 / 23FIG. 8B9 / 23FIG. 9B10 / 23FIG. 10B11 / 23FIG. 11AFIG. 1 1 B12 / 23Package hasPackage briefly remained reached -6C below -20CFIG. 12A FIG. 12B1202cPackage has remained at -12C for an extended period but did not reach -9CFIG. 12C13 / 23Package at point of shippingFIG. 13AFIG. 13B1400bFIG. 14A FIG. 14B15 / 231504a Saline x 1502b / iceDevice in -^Frozen Solution transit (obscures(package\ inside frozen) A _ k. — of device)1502a^ 11550( 6a 1508aFIG. 15B1500FIG. 15C16 / 23FIG. 16AFIG. 16B17 / 23FIG. 17ASponge (expanded after ice thaw)FIG. 17B1800bFIG. 18A FIG. 18B1800dSolutionSpring (thawed or re-frozen) (Compressed)FIG. 19A FIG. 19B3. Frozen balloons incorporated1 . Color coded saline under clear cover filled b$lloonso(freeging on packageat -18 C, -10 C, -4 C)4. Partial tha y (temperature above -10 C) indicated by which balloons have thawed (becoming round) Balloons frozen shaped moulds5. Complete thaw indicated (above -4 C) by all balloons thawing (becoming round)FIG. 2021 / 23FIG. 2122 / 23 0FIG. 2223 / 23FIG. 23

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