Indicator label for optically determining the concentration of an analyte in a fluid mixture - Patent Application 20070122997

Abstract

The present invention relates to an indicator label (1) for determining, in particular the concentration of, an analyte in a multi-component fluid mixture. The label (1) comprises a carrier layer (3), an adhesive layer (4) applied to the underside of the carrier layer (3), and a strip-shaped indicator substance portion (2) on the upper side opposite the lower side of the carrier layer. The indicator substance portion (2) contains an indicator substance that allows the presence, in particular the concentration, of the analyte to be determined by optical detection means, and the indicator substance portion (2) has a uniform thickness, i.e., extends uniformly in a direction perpendicular to the upper surface of the carrier layer. The present invention also relates to a tape (10) on which a plurality of indicator labels are arranged in a row, as well as methods for manufacturing such an indicator label and tape. The present invention also relates to a package (6) having such an indicator label on an inner label and a packaging machine (100) for applying the indicator labels to appropriate designated areas of the package before the sealing process.

Description

[Technical Field]

[0001] The present invention relates to a label with an indicator substance for the optical measurement of an analyte, particularly the concentration of an analyte, in a multi-component fluid mixture, particularly a gas, comprising a carrier layer, an adhesive layer applied evenly to the underside of the carrier layer, and an indicator substance portion on the side of the carrier layer opposite the adhesive layer, the indicator substance portion containing an indicator substance that allows the presence, particularly the concentration, of the analyte to be determined using optical means. The present invention also relates to a tape comprising a plurality of such labels arranged in series, and to a method for manufacturing such a label or label tape. The present invention also relates to a package comprising at least one label of the present invention, and to a packaging machine for packaging food or other delicate items in such a package. [Background technology]

[0002] For food and other delicate products, proper packaging is essential to ensure the longest possible shelf life. Once sealed, the package must be at least bacteria-resistant and stain-resistant. To further extend shelf life, airtight packaging is used, which, when properly sealed, allows little or no gas exchange between the atmosphere inside the package and the outside air. For this purpose, ideally, packaging is made of a non-porous material, which minimizes gas exchange by diffusion. In particular, plastic film packages, such as pouch-shaped packages, and two-part packages consisting of a bottom tray (which can be made of plastic or coated cardboard) and a sealing film, such as a transparent plastic film, are preferred. Metal foil or metal-coated plastic film can also be used to further inhibit particle diffusion through the package. Such airtight packages can create a modified atmosphere within the sealed package, which is why they are called MAP (Modified Atmosphere Packaging) industrial packages. This modified atmosphere is usually composed of one or more inert gases, primarily nitrogen for economic reasons. The inert gas is used to protect food and other items from oxidation by oxygen, which creates a highly reactive atmosphere. Thus, the goal of a typical MAP package is to achieve as low a residual oxygen level as possible inside the package after sealing. This modified atmosphere is intended to maintain the sealed package for as long as possible. Therefore, the weakness of the package lies not in the packaging material itself, even if the packaging material has some degree of diffusional permeability, but rather in the seal. During the sealing process, which is typically performed mechanically, imperfect sealing can occur for a variety of reasons. For one, the package may not be properly aligned during sealing, resulting in the sealing stamp sealing only partially in some areas or not at all. Furthermore, pieces of the packaged item may become trapped between the sealing elements of the package, compromising the seal.

[0003] To ensure that manufactured and distributed food products can actually be stored until their printed "best before" date, it is common to test the integrity of the seal of a package immediately after sealing. This test is performed by subjecting the package to mechanical or fluctuating pressures, which, if the seal is incomplete, will cause a rapid change in the modified atmosphere inside the package. In a subsequent step, the composition of the atmosphere is measured, and if it deviates from expected or previously measured values, the package is rejected.

[0004] Testing the atmosphere inside the packaging can be carried out in a destructive manner, for example by piercing the packaging with a measuring probe or lance and taking a sample of the atmosphere, however non-destructive methods are also known in the state of the art.

[0005] Optical methods for measuring the composition of an atmosphere, particularly residual oxygen, involve placing a fluorescent dye inside the packaging, for example by printing it on the inside of the packaging film. The dye is externally excited with light of the appropriate frequency, and the luminescence response is measured over time. If the system has been calibrated beforehand, the oxygen concentration can be estimated from these measured fluorescence parameters, particularly the luminescence intensity and / or decay time after excitation is stopped.

[0006] In the case of commonly used porphyrin dyes, the decay time shortens and the intensity of the luminescence response decreases significantly in the presence of oxygen. This phenomenon is called "oxygen-induced fluorescence quenching." Such methods are described, for example, in WO 2018 / 202784.

[0007] Another international patent application, WO 2017 / 125386, discloses a pouch packaging machine. The machine includes a means for printing a sensor element on a transparent area of ​​the packaging body, allowing the amount of remaining oxygen to be optically measured in a defined manner after the pouch is sealed. Since measurements are taken as the moving pouch passes the sensor, this document proposes designing the sensor element to be elongated, with its length aligned with the direction of pouch movement. This design allows the optical sensor more time to accurately detect the sensor element.

[0008] WO 2018 / 011307 discloses a packaging machine and method for packaging food products in two-part packages, each consisting of a shell-like lower tray arranged in a grid pattern and sealed with a transparent film. A fluorescent dye-containing sensor is printed on the underside of the film inside each package. An optical sensor in the packaging machine measures the amount of oxygen remaining in the sealed package and performs a leak test if necessary. Based on the measurement, an individual "best before" date is calculated for each package and recorded on an RFID label attached to the outside of the package.

[0009] EP 0 449 798 A1 discloses a method for quality control of packaged organic materials, in which a planar optical sensor element is inserted into the packaging. The sensor element contacts the food and can detect changes in the gas composition inside the packaging. This is achieved because the sensor element contains chemicals sensitive to various analytes. These analytes are decomposition products of the packaged food, and changes in their concentration can be optically detected. The sensor element consists of an indicator layer covered with a hydrophobic polymer layer facing the food. The opposite side of the polymer layer is attached to the inside of the packaging. Disadvantages of the proposed sensor element include its relatively large spatial extent and the lack of measures to design the indicator layer in a way that ensures a reliable measurement signal. Meanwhile, the sensor element is relatively bulky and has a large surface area, reducing the space available inside the packaging for the actual packaged goods. Furthermore, the resource consumption resulting from such a large sensor element is not very advantageous when used on a large scale, such as the hundreds of thousands of MAP packaging units produced daily in Germany alone.

[0010] WO 2022 / 055433 discloses an oxygen sensor and an oxygen sensor film label containing the sensor. The oxygen sensor includes a multilayer polymer electrolyte membrane and a dye carrier having a fluorescent dye. The oxygen sensor label includes such an oxygen sensor and is further covered with a food layer and an overlying protective layer. Furthermore, the underside of the oxygen sensor, or the oxygen sensor layer, includes an adhesive layer designed to attach the sensor label to the surface of the packaging. Disadvantages of this label include its relatively complex structure and resulting high manufacturing costs. Furthermore, its relatively large surface area requires a correspondingly large transparent area within the packaging to ensure accurate optical readings. Meanwhile, the presence of such a large, thick label within the packaging can be confusing and cumbersome for consumers.

[0011] A better solution, providing a simple and economical means for non-destructive optical measurement of the atmosphere inside a package, is disclosed in U.S. Patent Application Publication No. 2013 / 0177480. This document presents a freely positionable pressure measurement probe that can be optically measured from the outside and that comprises a solid composition containing a fluorescent dye on a carrier layer, the underside of which is provided with an adhesive layer for attaching the pressure measurement probe to the inside of the package. The relatively small pressure measurement probe can be manufactured from inexpensive materials, and it is proposed that it can optically measure, in particular, the oxygen concentration of the package atmosphere, and that it can be provided in a multi-unit array on a space-saving winding tape. However, a drawback of this solution is that no measures are taken to ensure sufficient accuracy of the fluorescence measurement. In particular, optical measurements of sealed packages are usually performed on packages passing in front of a stationary sensor. Therefore, to obtain a uniform signal, it is important that the dye density in the sensor's field of view does not change during the measurement period. In the case of the dotted probe label proposed in US Patent Application Publication No. 2013 / 0177480, the area of ​​the layer containing the fluorescent dye is too small, while on the other hand, the uniformity of the apparent dye density cannot be guaranteed, making it almost impossible to measure moving packages. Summary of the Invention [Problem to be solved by the invention]

[0012] Against this background, the object of the present invention is to provide a means for flawlessly determining an analyte, in particular its concentration, in a package that can be produced quickly and cheaply and that allows accurate measurement even in the presence of relative movements between the label and the optical sensor. Furthermore, the package provided with this means should be able to be graphically designed, in particular freely printed, if possible, without taking into account the technical means provided to enable the concentration measurement. [Means for solving the problem]

[0013] This object is solved in a first aspect of the present invention by an indicator label according to claim 1 which can be produced by the method according to claim 10, and by a tape comprising a plurality, in particular a large number, of such labels arranged in an array according to claim 12 which can be produced by the method according to claim 13. In a further aspect, the present invention proposes a package having at least one such indicator label on the inside facing the optionally regulated atmosphere according to claim 14. In a third aspect, the present invention relates to a packaging machine according to claim 15 and to a method according to claim 20 for packaging food or other delicate items in packages having indicator labels according to the invention.

[0014] A first aspect of the present invention is an indicator label according to any one of claims 1 to 9. This label comprises, in a generally known manner, a support or carrier layer having a flat adhesive layer applied to its lower surface, and the carrier layer carrying an indicator substance portion on its upper surface opposite the lower surface. The indicator substance portion contains an indicator substance whose properties change in response to the presence, particularly the concentration, of an analyte so as to be optically detectable from the outside.

[0015] In particular, the indicator substance may be a luminescent dye, specifically a fluorescent or phosphorescent dye, that, when excited with light of a particular wavelength, emits light of a different wavelength. The luminescent parameters depend on the presence of the analyte, and generally also on its concentration, making it possible to measure the concentration of the analyte using these luminescent dyes.

[0016] For example, in the case of porphyrin dyes, the presence of oxygen reduces both the decay time and intensity of the fluorescence response to optical excitation. In other words, in the presence of oxygen, the fluorescence emitted from the dye is weaker, and the fluorescence signal decays more rapidly after the excitation light is turned off than in the absence of oxygen. These changes become more pronounced as the oxygen concentration increases. Therefore, by measuring the intensity and / or decay time of the fluorescence response signal, the oxygen concentration near the dye can be measured.

[0017] The indicator label according to the present invention is characterized by a uniform thickness of the indicator substance portion, which in some embodiments is formed as an indicator (substance) layer covering the entire surface of the label or as a band of indicator (substance) extending across the surface area. The relative thickness deviation of the indicator substance portion varies from point to point, preferably by no more than 10%, more preferably no more than 1%, at least in the longitudinal direction parallel to the surface of the support layer. This ensures that the visible surface density of the indicator substance detectable by the optical sensor remains constant as the label passes through the detection range of the sensor during optical measurement of the indicator label. This ensures that a uniform optical signal is detectable, and that relative movement between the sensor and the label does not adversely affect the accuracy of the analyte measurement.

[0018] The thickness of the indicator layer does not necessarily have to be uniform in two mutually perpendicular directions. Rather, it is sufficient for the indicator substance portion to have a uniform thickness in only one direction, i.e., for the indicator substance portion to have a band-like region of uniform thickness. Thickness variations in the direction perpendicular to the direction of uniform thickness are acceptable, provided that relative movement between the sensor and the indicator label during measurement is limited to occurring only in the direction parallel to the direction of uniform thickness.

[0019] In preferred embodiments, indicator labels according to the invention advantageously have relatively small dimensions of only a few millimeters and, in particularly preferred embodiments, are provided in a number of successive positions on a continuous strip of material wound into a roll.

[0020] The indicator label is produced by printing the indicator substance portion onto a blank label or label substrate according to the method of the present invention. For this purpose, a blank label is first provided, which comprises a carrier layer and an adhesive layer underneath. In practice, the side of the adhesive layer opposite the carrier layer should be covered with a release coating, using known methods, that only lightly adheres to the adhesive layer, in order to prevent the label from unnecessarily sticking.

[0021] The blank label may already have an outer shape that corresponds to the shape of the final label. Preferably, however, a blank is provided that includes a label portion and a surplus portion adjacent to or surrounding the label portion. The indicator substance portion is printed on this blank so that it extends beyond at least one, preferably two, particularly opposite end regions of the label portion. The self-leveling properties of the ink used result in a substantially uniform distribution of the indicator substance over the entire area of ​​the indicator substance portion.

[0022] The portion of the indicator substance extending onto the excess portion is removed together with the excess portion itself after drying the printed indicator substance, resulting in an indicator label according to the present invention having an indicator substance portion with a uniform thickness at least in a direction parallel to the surface of the carrier layer.

[0023] For example, blank labels can be used in which the label portion is circular or oval in shape and is completely surrounded by a surplus portion. Such blanks can be produced, for example, by forming a label portion of the desired shape from a blank including a support layer having an adhesive layer underneath, preferably with a release coating thereon. During this process, care must be taken not to damage the release coating so that the label portion and the surplus portion can remain spatially connected. Various indicator substances can be printed onto such blanks.

[0024] In some embodiments of the present invention, the indicator material portion is printed to cover the entire label portion and extend into the excess portion around the entire periphery. During the drying process, solid particles dispersed in the liquid indicator material tend to collect at the edges of the printed spot, resulting in the thickest area after drying. Conversely, the amount of indicator material is lowest at the center of the printed spot after drying. However, the thickness gradient is relatively low away from the edge, e.g., more than 10% of the extent of the indicator material portion in this direction. This ensures that the center of the indicator material portion remaining on the label portion maintains a substantially uniform thickness after the excess surrounding the label portion is removed, particularly peeled off. In these embodiments, the thickness also remains uniform in the direction perpendicular to the surface of the label.

[0025] In another embodiment, the division of the support layer into label and surplus portions is done only after printing, which has the advantage of allowing a cleaner separation between the portion of indicator material on the label portion and the (thicker) portion of indicator material on the surplus portion.

[0026] A drawback of the above-described embodiment of the label of the present invention is that in order to detect a label that passes the sensor at a relatively high speed, the label needs to have a certain spatial extension. For example, if the label passes the sensor at a speed of 1 meter per second, 10 data points are needed for a reliable optical measurement, and the sensor records a data point every 1 millisecond, the label needs to have a length of at least 10 millimeters in the direction of movement.

[0027] According to the above embodiment, for a uniformly coated indicator substance label having a circular shape, the size is about 80 mm. 2The indicator substance must cover a surface area of ​​approximately 10 mm. However, the fluorescent dyes used for oxygen detection are relatively expensive, costing several thousand euros per liter. Therefore, for economic reasons, it is highly desirable to use these substances in a resource-saving manner. Furthermore, a 10-millimeter extension perpendicular to the direction of movement is not necessary or desirable, since variations in the width of the indicator substance portion can lead to variations in the measurement signal. This can be avoided by using labels with a rectangular outline, or can be corrected during the measurement if the shape of the indicator substance portion is known. In the latter case, this step can be avoided if the indicator substance portion itself has an at least approximately rectangular shape, with the long side facing the direction of movement.

[0028] In the context of the present invention, the shape of the label portion itself is of secondary importance. The label portion or finished indicator label can be circular, oval, rectangular, or any other functional shape. Circular or rectangular (e.g., square) shapes are most practical for ease of manufacture and handling.

[0029] On the label part or label, the indicator substance portion is preferably printed in the shape of a rectangle, with two opposite ends of the rectangle extending beyond the label part or label itself and also disposed in an excess portion during the manufacturing process according to the method of the present invention. After the liquid indicator substance or the ink containing the indicator substance has dried, the excess portions on both sides are removed, leaving only a rectangular, approximately rectangular strip on the surface of the support layer, excluding the short ends which may be curved.

[0030] According to the present invention, the strip of indicator material has a desired uniform thickness in the longitudinal direction, with thickness variations perpendicular to this direction, but this is not a problem if the label is applied to a packaging machine with the long sides of the rectangular strip of indicator material parallel to the direction of travel of the packages through the packaging machine.

[0031] The method of the present invention allows the individual production of indicator labels according to the present invention. Preferably, however, the labels are produced in roll form. That is, the method of producing an indicator label roll, as also claimed, provides a strip-shaped blank consisting of an adhesive layer embedded between an upper carrier layer and a lower release layer, from which the indicator label portions are separated simultaneously or successively into the desired shape. This separation can be carried out by punching or cutting, for example, by laser cutting. However, care must be taken during this process to cut only the carrier layer and, if necessary, the adhesive layer, without damaging the release layer. To achieve this, it is advantageous to select a material for the adhesive / release layer that is less susceptible to separation than the carrier layer in the separation method used. Adjacent carrier layer regions surrounding successive indicator label portions subsequently form a waste portion unless further divided. As described above, in the method of the present invention, the indicator substance spots are printed in one location on the label section, preferably two locations, particularly two opposing locations, or in some embodiments, so that the spots extend beyond the label section all the way around and end in the excess portion. After printing, the indicator substance ink is allowed to dry naturally or actively, and the excess portion is removed after drying. To simplify this in industrial production, instead of a large, continuous excess portion, it can be divided into small, easily machine-separable portions, for example, during the label section separation process. After the excess portion is removed, what remains is a roll of the indicator labels of the present invention, which consists of a carrier layer, a fully coated lower adhesive layer, and the indicator substance spots on top of the carrier layer. The indicator substance spot may, as mentioned above, cover the entire top side of the carrier layer or only a portion thereof, for example in the shape of a rectangle with uncovered areas to the left and right of the label portion, however it is preferred that the indicator substance spot is flush with the label or label portion on one side, and preferably on two opposite sides. Printing of the indicator substance spots may be performed before or after separation of the label portion.

[0032] Another aspect of the present invention is a package for food or other delicate items, such as a modified atmosphere package, to which an indicator label according to the present invention is adhered in an externally visible position. The package may be, for example, a pouch having at least one transparent area, or a tray-type package closed with a top film. Here, "externally visible" is understood to mean that the location is transparent to externally irradiated excitation light and also sufficiently transparent to internally incident fluorescence, which is emitted from the indicator substance in the indicator substance spot on the indicator label and which typically has a different (lower) frequency than the excitation light. The packaging of the present invention may be unprinted or may have printing in visible, i.e., sufficiently transparent, areas, but this printing is designed to be sufficiently transparent to the excitation light and the fluorescence, which can be achieved by using inks for printing that are transparent to the excitation light and the fluorescence. Alternatively or additionally, the printed material may have printed and non-printed areas throughout, at least on the surface area occupied by the indicator label inside the packaging, with the non-printed areas occupying at least 5%, preferably at least 10%, particularly preferably at least 25% of the area of ​​the indicator label. The printed and non-printed areas are preferably arranged alternately, particularly in the form of a one-dimensional (line) or two-dimensional grid of dots. The height and width of each non-printed area are greater than the wavelengths of the excitation light and (longer wavelength) fluorescence. In a particular embodiment of the packaging, the printing is applied by digital printing and comprises a grid of raster dots, the distance between adjacent points of the grid being at least 1.05 times, in particular at least 1.1 times, for example 1.2 to 2.0 times the radius of the grid points.

[0033] A third aspect of the present invention is a packaging machine for packaging food or other delicate items in a package according to the previous aspect, the machine comprising labelling means for adhering an indicator label of the present invention to a suitable, in particular transparent, position on the inside of the package in contact with the atmosphere inside the package before sealing the package.

[0034] Furthermore, the packaging machine of the present invention preferably includes at least one optical sensor for detecting and measuring indicator labels within the sealed packaging. Depending on the indicator labels and sensors used, this sensor can be used to measure at least one analyte, e.g., the gaseous components of the modified atmosphere, inside the packaging after production, thereby enabling the quality of the atmosphere to be determined. This can provide additional information, such as the expected minimum shelf life. In principle, this can also be extended to packaging filled with liquids, provided that appropriate indicator substances and labels are used.

[0035] In some embodiments, there are multiple optical sensors. These sensors can be positioned substantially parallel to one another and transverse to the direction in which the packages are conveyed through the machine, allowing multiple packaging lanes to be measured simultaneously without rapidly changing the sensor's position. Alternatively or additionally, there are at least two optical sensors for each packaging lane in the conveying direction, for example, to measure the atmosphere in each package at two points after sealing. To detect leaks, a vibration or pressure change path can be arranged between the optical sensors.

[0036] Since packaging used in practice is often not completely transparent, but has alternating transparent and printed or covered areas, and the transparent areas suitable for adhering the label of the present invention are usually in different positions for each packaging, it is important that the labeling means and optical sensor can be aligned transversely to the lateral position of the transparent areas to which the indicator label will be adhered. This alignment can be achieved by manually adjusting the labeling means and / or optical sensor before operation with a particular packaging design. Alternatively or additionally, the labeling means and / or optical sensor can be mounted so as to be laterally movable, for example, on a cart running on lateral rails.

[0037] Even for a given package design, the transparent areas may deviate from their expected positions both laterally and vertically, and this tolerance must be corrected. Therefore, in a further advantageous embodiment of the machine, optical detection means are provided that measure the exact position of the transparent area for each package individually. The labeling means and / or the optical sensor are then aligned laterally for each package based on the measured position for the specific package, so that for each package, a label is adhered by the respective labeling means in exactly the same position relative to the edge of each target transparent area, and the relatively narrow detection area of ​​the optical sensor can be accurately aligned with the lateral position of the label. To achieve this, as disclosed as an option in the above embodiment, the labeling means and, if applicable, the optical sensor must be mounted so as to be able to move laterally.

[0038] Here, and elsewhere in this application, "transparent" does not necessarily refer to transparency in the visible spectrum, but rather to transparency of the packaging in the wavelength range relevant to optical measurement of the indicator substance, unless expressly stated otherwise.

[0039] Furthermore, packaging machines according to this aspect of the invention preferably use a strip of indicator labels of the invention, on which the indicator labels are sequentially arranged. These can be fed, for example, from a conveyor (belt) arm having means at a distal end for peeling the labels and applying them to the desired location on the package. The peeling means can include, for example, a deflection roller with a small radius, so that as the indicator label strip passes over the deflection roller on the side opposite the release layer, the label is peeled off on one side due to the rigidity of the carrier layer due to the small radius of the deflection roller. The peeled side of the label can then be brought into contact with the identified preferred location on the package and further peeled from the label strip so that it can be finally and completely transferred onto the package.

[0040] In these preferred embodiments, the distal end of the conveyor belt arm can be positioned in at least one direction transverse to the direction of movement of the packaging machine so that the label to be applied to the package is located in a transparent area recognized by the optical detection means as a suitable or targeted location. This can be achieved, for example, by the arm being mounted to pivot about the z-axis, or yaw-axis. Alternatively or additionally, the arm can be mounted to move laterally, for example, using a slider. It is further contemplated that the distal end of the conveyor belt arm can be repositioned in both directions within the plane of the package, i.e., vertically. To this end, the arm can be mounted to rotate about the y-axis, or pitch-axis, or be vertically movable.

[0041] This method according to this aspect of the invention for packaging food or other delicate items in a package according to the second aspect of the invention comprises two steps:

[0042] In a first step, an indicator label according to the first aspect of the invention is applied by a labelling means of a packaging machine to a randomly selected or pre-designated transparent area on the side of the package that will subsequently come into contact with the atmosphere inside the sealed package, where "randomly selected" means that the labelling means can be freely oriented with respect to a reference point on the package at least prior to operation with a particular package design, and preferably dynamically during operation, e.g. to allow the packaging machine to process different package designs simultaneously in the same run, or to compensate for manufacturing-related tolerances regarding the location of the transparent area for the indicator label on the package.

[0043] In a second step, an analyte, e.g., a gaseous component, is measured in the package using an optical sensor that is manually or automatically positioned in a selected area of ​​the package. This allows for a subsequent check of the atmosphere and a determination of the expected shelf life. Furthermore, the quality of the seal can also be checked by performing a second measurement of the analyte, e.g., a gaseous component, at different time intervals for each package by spatially moving the optical sensor or by using a second optical sensor positioned further back in the transport direction.

[0044] Further advantageous embodiments are contained in the dependent claims and are explained in more detail below, which in any combination, unless expressly mutually exclusive, form part of the invention.

[0045] The indicator label according to the first aspect of the present invention has a relative thickness deviation of no more than 10%, in particular no more than 1%, in at least one direction, preferably in both directions, perpendicular to the upper surface of the carrier layer. The preferred absolute thickness of the indicator layer or indicator layer spot is 5 to 500 micrometers, in particular 1 to 100 micrometers.

[0046] The carrier layer of the indicator label according to the invention can consist of cellulose or plastic, in particular polypropylene or polyester, and preferably has a thickness of 20 to 1000 micrometers, particularly preferably 50 to 200 micrometers.

[0047] The adhesive layer that adheres the suitable indicator label to the inside of the package preferably comprises or consists of a food-compatible adhesive.

[0048] The indicator substance portion provided on the upper surface side of the carrier layer of the indicator label according to the present invention is suitably elongated, with a length to width ratio of 2 to 20, preferably 5 to 10. In particular, the indicator substance portion is preferably rectangular in shape with a width of 0.5 to 2 mm and a length of 4 to 10 mm. In a particularly preferred embodiment, the indicator portion is about 1 mm wide and about 7 or 8 mm long.

[0049] In some embodiments of the indicator label according to the invention, the indicator substance portion is flush with the edge of the carrier layer in at least one location, preferably two locations, especially two opposite locations, thereby maximizing the length of the indicator substance portion or strip.

[0050] The adhesive layer preferably has a thickness of 10 to 200 micrometers, in particular 50 to 100 micrometers. In preferred embodiments, the indicator label of the present invention is substantially transparent to visible light and in particular also colorless, so that when the indicator label is inserted into a package, it is as unobtrusive as possible to the consumer opening the package, and so does not or only minimally detracts from the overall appearance of the package. In a preferred embodiment, the indicator substance in the indicator substance portion is a luminescent, in particular a fluorescent dye, with at least one luminescence parameter, such as relative intensity upon excitation, excitation frequency, emission frequency and / or decay time, depending on the presence of the analyte, and in particular at least one or more of these parameters vary continuously with the concentration of the analyte in the fluid being analyzed, which may in particular be a gas mixture. A package carrying an indicator label according to the second aspect of the present invention may consist of a flat or bowl-shaped lower part sealed at the top by an at least partially transparent film, in which case the indicator label of the present invention is preferably adhered to the underside of the top film. In some embodiments of the packaging machine according to the third aspect of the invention, the at least one optical sensor is designed to be manually aligned laterally with respect to the side edge of the sealed package, although preferably this can also be done automatically, thereby making it movable in particular laterally. Furthermore, the sensor preferably scans the indicator label passing through the detection / scanning field after alignment. This can be achieved, for example, by scanning the detection field at a low scanning speed. If such an indicator label is detected during scanning, optical measurement of the label is performed, for example, by scanning the detection field at a measurement speed higher than the scanning speed. The scanning speed can be, for example, 50 to 500 Hz, preferably 100 to 200 Hz, and the measurement speed can be, for example, 100 to 2000 Hz, preferably 500 to 1000 Hz. In a further preferred embodiment, the sensor issues a warning or indication if a supposed indicator label is not detected during scanning, for example because the indicator label is completely missing or partially or completely adhered by the labeling means to the outside of the transparent area. The sensor's assumption of the presence of an indicator label can be determined based on a time window during which the transparent area of ​​the individual package passes through the measurement area. These time windows can be pre-calculated based on the known extent of the transparent area in the longitudinal direction, the transport speed of the package, and a defined starting point. Alternatively or additionally, the time window can be calculated based on the position measured by optional additional optical detection means and the known distance along the transport direction of the package or packaging part, e.g., in the form of a lower packaging part and an associated sealing film, monitored by these detection means. [Brief explanation of the drawings]

[0051] Further features, characteristics and advantages of the present invention will become apparent from the embodiments shown below with reference to the drawings, which are intended to be illustrative of the invention only and do not limit its generality.

[0052] The details are as follows:

[0053] [Figure 1] 1A is a schematic cross-sectional view of an indicator label according to a first embodiment of the present invention, and FIGS. 1B and 1C are top views of various modifications of the indicator label according to the first embodiment. [Figure 2] 1A is a schematic cross-sectional view of an indicator label according to a second embodiment of the present invention, and FIGS. 1B and 1C are top views of various modifications of the second embodiment of the indicator label. [Figure 3] 3A is a cross-sectional view of a blank indicator label showing the start of the manufacturing method of the indicator label of the present invention. (B) is a top view of the blank indicator label of FIG. 3A, showing the separation line between the label portion and the excess portion and the outline of the indicator material portion to be printed. (C) is a top view of the blank indicator label of FIG. 3B after separation of the label portion and printing of the indicator material portion. (D) is a vertical cross-sectional view of the blank indicator label of FIG. 3C, taken along line DD. (E) is a perspective view of the completed indicator label immediately after removing the excess portion. [Figure 4] 1 is a schematic diagram showing a rolled state of an indicator label tape according to the present invention, in which a plurality of indicator labels are sequentially disposed on a tape-like release layer. [Figure 5] 5(B) is a schematic top view of the initial portion of the semi-finished indicator label tape of FIG. 5(A) at the start of the manufacturing of the indicator label tape of the present invention. (B) is a schematic top view of the initial portion of the semi-finished indicator label tape of FIG. 5(A) after the carrier layer has been divided into an excess portion and four circular label portions, and an indicator substance portion has been printed on each label portion. (C) is a schematic longitudinal cross-sectional view of the semi-finished indicator label tape taken along line CC in FIG. 5(B). (D) is a schematic cross-sectional view taken along line DD in FIG. 5(B). (E) is a schematic perspective view of the initial portion of the completed indicator label tape of the present invention after the excess portion of the semi-finished indicator label tape of FIG. 5(B) has been removed. [Figure 6] 1 is a schematic cross-sectional view of a package according to the present invention having an indicator label according to the present invention therein; [Figure 7]FIG. 7 is a schematic perspective view of a packaging machine according to the present invention using an indicator labelling means for producing packages such as those shown in FIG. 6. DETAILED DESCRIPTION OF THE INVENTION

[0054] Figures 1(A)-(D) show schematic diagrams of various modifications of the first embodiment of the indicator label of the present invention. In Figures 1(B)-(D), three possible modifications of the indicator label are shown in top view. The indicator label 1 has a circular outer shape in Figure 1(B), an elliptical or oval outer shape in Figure 1(C), and a rectangular outer shape in Figure 1(D). Other outer shapes are also possible, such as a square or rectangle with slightly rounded corners.

[0055] The cross section shown in Figure 1(A) is common to all the variations and is taken along dashed line AA shown in Figures 1(B) to 1(D). The indicator label comprises a laminate structure consisting of a carrier layer 3 located directly above an adhesive layer 4.

[0056] The adhesive layer 4 is used to facilitate adhesion when attaching the indicator label to the inside of the package to be monitored (see Figure 6 and description below). The adhesive layer is covered with a release layer 5 for practical reasons only prior to use. Prior to application (gluing or attachment) of the indicator label, the release layer 5 is removed.

[0057] The release layer 5 is made of a material on the side facing the adhesive layer to which the adhesive / adhesion promoter of the adhesive layer 4 only weakly adheres and which allows for easy removal. The entire adhesive layer 4 can also be made of such a weakly adhesive material. Examples include fluoropolymer plastics such as PTFE (polytetrafluoroethylene). Alternatively, materials such as paper or cardboard coated with PTFE can be used.

[0058] The carrier layer 3 serves to mechanically support the indicator substance portion 2, and in this embodiment, the indicator substance portion 2 occupies the entire upper surface of the indicator label 1, and is therefore also referred to herein as the indicator substance layer 2 or simply as the indicator layer 2. The indicator substance layer 2 is therefore flush with the underlying carrier layer 3 over its entire surface.

[0059] Indicator layer 2 contains an indicator substance that is sensitive to the analyte being measured, meaning that the presence of the analyte causes an optically detectable change in a property of the indicator substance. For example, the indicator substance may undergo a change in color, structure, absorption properties, emission properties, or the way it reflects polarized light upon binding or reacting with the analyte.

[0060] The indicator substance can also be a luminescent (fluorescent or phosphorescent) dye that, when excited by light of a particular frequency, emits light of a different, usually lower, frequency. When the excitation is stopped, the luminescent response typically decays exponentially with a time constant.

[0061] In embodiments of the indicator label of the present invention designed to measure oxygen as an analyte, the indicator material portion may comprise a porphyrin as a fluorescent dye. The use of this type of material results in quenching of fluorescence with increasing oxygen concentration, resulting in a decrease in emission intensity for a particular excitation and a short decay time after excitation is stopped. By measuring the intensity (after pre-calibration) and / or decay time, the oxygen concentration in an atmosphere in contact with the indicator label can be determined.

[0062] The indicator layer can also contain several different indicator substances. These different substances can be sensitive to various analytes, allowing for the optical detection of the presence and / or concentration of multiple analytes. Two or more substances in a multi-component indicator layer may be sensitive to the same analyte, but in different ways or at different intensities, allowing for redundant measurements or compatibility with different optical sensors.

[0063] The advantage of covering the entire top surface of the indicator label with the indicator substance portion in the form of an indicator layer is that a larger optical detection area is obtained compared to covering only a portion of the top surface, which allows for more accurate concentration measurements. Furthermore, when combined with the manufacturing method of the present invention (described in more detail below), the thickness of the indicator layer can also be made more uniform.

[0064] Specifically, in the manufacture of the indicator label of the present invention according to the first embodiment shown in Figures 1(A)-(D), the manufacturing process of the present invention minimizes thickness variations not only in one dimension but also in two spatial dimensions, thereby keeping the relative variations to 10% or less, or even 1% or less.

[0065] 2(A)-(D) show various schematic diagrams of modified examples of the indicator label of the present invention according to the second preferred embodiment. The laminated structure shown in Figure 2(A) and the structure including the possible shapes shown in Figures 2(B) to (D) are similar to those of the first embodiment, but the main difference is that in the second embodiment, a strip-shaped indicator substance portion 2 is provided on the upper surface of the carrier layer 3 instead of a full-surface indicator substance layer as in the first embodiment.

[0066] Another difference is that the corners of the external shape shown in Figure 2(D) are (more) rounded.

[0067] In the second embodiment, the indicator strip 2 is flush with the edge of the carrier layer 3 on its opposing short sides, but leaves part of the carrier layer 3 free on its long sides. This results in a significantly smaller total surface area and amount of indicator material than in the first embodiment. This has the advantage that less of the typically expensive indicator material is used per indicator label, while still allowing reliable detection and measurement of the optical change in the indicator material during relative movement between the label 1 and the optical sensor.

[0068] To ensure this functionality, the indicator strip is designed to be as long as possible and to run flush with the edge of the carrier layer. When using the label, the indicator strip 2 must be carefully aligned so that its long side is as parallel as possible to the direction of relative movement.

[0069] 3(A) to 3(E) illustrate the manufacturing process according to the present invention, using the manufacturing of an indicator label according to the second embodiment as an example. As shown schematically in Figure 3(A) (cross-section) and Figure 3(B) (top view), the process begins with the preparation or manufacture of a blank indicator label 1. Blank 1 consists of a laminate structure, arranged in this order from bottom to top: a release layer 5, an adhesive layer 4, and a carrier layer 3. These layers have similar properties (composition, thickness, etc.) to those used in the first and second embodiments of the indicator label.

[0070] In the top view of Figure 3(B), the intended segmentation into a circular label portion 11 and a surrounding complementary excess portion 12 is shown by dashed lines. Superimposed by dotted lines 2' are strip-shaped indicator substance portions 2 that are to be printed on the top surface of the carrier layer after segmentation. The cross section shown in Figure 3(A) is taken along section line AA in Figure 3(B).

[0071] 3(C) shows a top view of the blank 1 after two steps have been performed: separating the label portion 11 from the excess portion 12, and printing a strip of indicator substance portion 2 onto the carrier layer. As shown, the strip of indicator substance portion 2 is printed so that its center coincides with the center of the label portion 11 and two opposing short end regions extend into the excess portion 12.

[0072] The advantage of this configuration becomes clear from Fig. 3(D), which shows a longitudinal section of the blank 1' of Fig. 3(C) along line DD. It can be seen that the separation into the label portion 11 and the surplus portion 12 only extends through the carrier layer 3 and adhesive layer 4, but not through the release layer 5. This has the advantage that, after separation into the label portion and the surplus portion, the indicator strips 2 remain close to each other for printing purposes.

[0073] In other embodiments of the method according to the invention, the printing of the indicator strip 2 is carried out before dividing the blank 1' into the two parts, the label part 11 and the surplus part 12. In these embodiments, it is also possible to cut the release layer 5 and completely separate the label part 11 from the surplus part. However, this has the disadvantage that the finished indicator label may be difficult to peel from the release layer 5, especially if the release layer 5 adheres relatively well to the adhesive layer 4 and / or if the release layer 5 is relatively thin and flexible. Therefore, even in the printing-first method embodiments, it is advantageous to subsequently divide only the carrier layer 3 and the adhesive layer 4.

[0074] The indicator band is printed onto the surface of the carrier layer 3 as an ink in the form of a liquid suspension, dispersion, or solution of the indicator substance and, optionally, other substances, such as hydrophobic and / or film-forming substances. The printing process plays no role in the context of the present invention. The solvent in this ink necessarily dries faster at the edges of the indicator band 2 than in the center. This causes the indicator substance and other solids to accumulate at the edges of the indicator band 2, forming thickened regions in the opposing edge regions 2a and 2b of the indicator band 2, as shown in FIG. 3(D). The extent to which the thickened edge regions 2a and 2b extend beyond the edges of the label portion 11 is advantageously selected so that the portion of the indicator band 2 directly overlying the label portion has a uniform thickness. The residual thickness variation of the indicator band above the label portion is preferably 10% or less, more preferably 1% or less.

[0075] 3(E), the indicator label 1 of the present invention can be produced from the blank 1 thus processed by removing, for example by peeling, the excess portion 12 together with the thickened end regions 2a, 2b of the indicator band. To prevent damage to the portion of the indicator band 2 above the label portion during removal of the excess portion 12 and the thickened end portions, in a preferred embodiment method, the indicator band is printed first, and then the blank 1' is divided into the label portion 11 and the excess portion 12. The division is advantageously performed by punching or cutting, either mechanically or by laser.

[0076] FIG. 4 is a schematic perspective view of an exemplary embodiment of an indicator label tape of the present invention, which can be used, for example, in the packaging machine shown in FIG. 7 and described in more detail below. Specifically, as shown, tape 10 carries a strip-shaped release layer 50 (hereinafter also referred to as release tape 50) on one side thereof, a plurality of indicator labels according to the second embodiment, in a variant having a circular outline corresponding to FIGS. 2A, 2B, and 3E, arranged sequentially. However, within the scope of the present invention, release tape 50 may carry other embodiments and / or variants. Different embodiments and / or variants may also coexist on the same tape 10, 50. As shown in the figure, indicator label 1 on release tape 50 is oriented so that the long side of indicator strip 2 is parallel to the longitudinal direction of tape 10, 50. However, other orientations are possible within the context of the present invention, such as orienting the long side of indicator strip 2 perpendicular to the longitudinal direction of tape 10, 50.

[0077] 5(A) to 5(E) show, in a number of schematic diagrams, an embodiment of the method of the present invention for producing the indicator label tape 10 of FIG. 4 described above. 5A is a perspective view of the front portion of the tape blank 10', with four detachable label portions 11' shown in dashed lines and surrounded by a surplus portion 12'. The tape blank 10' comprises three identical tape-shaped layers stacked in sequence: a release layer 50, an adhesive layer 40, and a carrier layer 30. FIG. 5(B) shows a schematic plan view of the initial section of FIG. 5(A) after dividing at least the carrier layer 30, preferably both the carrier layer 30 and the adhesive layer 40, into label sections 11 and excess sections 12 and printing one indicator strip 2 per label section. The excess section 12 can be divided into smaller sections to facilitate subsequent removal from the release layer. The order of the two steps of dividing and printing is optional; in some embodiments, dividing occurs before printing, while in other embodiments, the reverse is true. The former order allows the print head for the indicator strip 2 to be accurately aligned with the label sections using the visible outline of the dividing line between 11 and 12. The latter order facilitates cleaner removal, particularly with minimal or no damage to the indicator strip.

[0078] Figures 5(C) and 5(D) show longitudinal and sectional views along lines CC and DD, respectively, of Figure 5(B). As shown in Figure 5(C), the indicator strip has end regions 2a and 2b that are thicker after drying. In a preferred embodiment, the length of the printed indicator strip 2 is intentionally selected so that these end regions 2a and 2b are positioned above the excess portion 12 and are removed together with the excess portion 12 in a final step. As shown in Figure 5(E), the completed indicator label strip 10 of the present invention remains, with the indicator label 1 aligned as shown on its peel strip 50. As mentioned above, the division into the label portion 11 and the excess portion 12 can be performed first, or vice versa. In the former case, each indicator strip 2 forms a continuous mass after drying, whereas in the latter case, the end regions 2a and 2b are separated by gaps from the central region above the label portion during division / separation, e.g., by die-cutting. These two variations are indicated in FIG. 5(C) by the dashed lines between the central and end regions 2a, 2b.

[0079] The cross-sectional view of Figure 5(D) shows the lateral division of the carrier layer 30 and adhesive layer 40 and the thickness profile in the lateral direction of the indicator band 2. As in the longitudinal direction, drying of the printed indicator material results in a profile with thicker end regions 2c. However, as long as the relative movement between the optical sensor and the indicator label 1 occurs primarily parallel to the longitudinal direction of the indicator band 2, this profile does not pose a problem during optical measurements.

[0080] The figure shows a tape 10 with indicator labels 1 arranged sequentially in a single row. However, it is equally conceivable within the scope of the present invention to manufacture a wider tape with two, three, or more rows of indicator labels. The indicator labels can also be arranged in a square, triangular, or other grid pattern, or in no particular regular order.

[0081] 6 shows a schematic longitudinal cross section of a packaging system with an indicator label of the present invention affixed to the inside thereof. The packaging 6 comprises a bowl-shaped base 61 covered on top with a thin film 62, the edges of which are sealed to ensure an airtight seal, in a known manner.

[0082] The package contains a product 7, such as a food product, and a modified atmosphere (not shown), i.e., an atmosphere with a composition different from that of the Earth's normal atmosphere, consisting of approximately 79% nitrogen and 21% oxygen, with trace gases, primarily carbon dioxide. The presence of an oxygen-free, inert gas atmosphere, e.g., nitrogen and / or noble gases, within the package can slow the deterioration of the product 7, thereby extending its life or (minimum) shelf life. Ideally, the goal is to achieve 0% oxygen. This is mathematically impossible to achieve in practice, and packages manufactured using industrial mass production processes, in particular, typically fall short of this goal, typically resulting in residual oxygen levels of 0.5% to 1%. However, even in such a low-oxygen atmosphere, the shelf life of the food product can be significantly extended. The amount of residual oxygen present within the package 6 can be measured by optically reading an indicator label 1 according to the present invention, which is affixed to the interior of the package 6 and is in contact with the atmosphere and contains an oxygen-sensitive indicator substance. For this purpose, the label is placed in the transparent area 620 of the top film 62. Here, "transparent" refers to transparency to the frequencies of light relevant to the measurement, and not necessarily transparency to visible light.

[0083] 7 shows a schematic representation of a packaging machine 100 for producing packaging units such as those shown in FIG. 6, the packaging machine having labelling means for applying, inter alia, indicator labels 1 according to the invention. For example, here these are designed as two arms 120 pivotable about the z and y axes, on each of which an indicator label strip 10 according to the invention is attached in a wound state and which is unfolded by a deflection roller 122 arranged in the region of the distal end 121 of the arm 120. Due to the bending of the strip 10 that occurs during deflection, the label arranged at the leading end 121 is peeled off at its lower end. By arranging the deflection roller 101, which transports the film strip 162 in the direction of the arrow at a speed V, the part of the film 162 that will become the inner part is transported just before the distal end of the labelling arm 120, so that a peel-off label can be glued to the inner side.

[0084] The optical detection means 130 is, for example, a camera system, which, if necessary, detects a transparent area 162 of the film to which the indicator label 1 is attached so that it can be optically detected from the outside after the package is closed and sealed. The optical detection means 130 is useful when the film 162 has areas that are opaque to the light used for optically measuring the indicator label 1, for example when the film is partially printed, metallized, or partially made of a different material (for example, a combination of metal and plastic film), but these areas are not always in the same position due to manufacturing tolerances or because films of different designs are intentionally used in a single packaging process. The transparent areas intended for and used as indicator labels are shown here by way of example as rectangular areas 1620 in two parallel rows within the film 162, but they are not always positioned at exactly the same location in both the horizontal and vertical directions of the film 162. In some embodiments of the packaging machine, vertical deviations are corrected by controlling the payout speed of the indicator label strip 10 on each arm 120, increasing the speed when the optical detection means reports a small distance between successive transparent areas and decreasing the speed when the distance is large. Vertical deviations can alternatively or additionally be corrected in this manner if the labeling arm 120 can also be pivoted about a y-axis y1 or y2 as shown. However, horizontal deviations can only be corrected by repositioning the arm tip 121 laterally. This can be done by moving it about the respective z-axis z1 or z2, as shown in FIG. 7. Alternatively (or additionally), the arm 120 can be mounted so that it can move laterally, i.e., in the y-direction. Using other means (not shown) of the packaging machine 100, the format 161 of the lower package 61 to be produced is conveyed at the same speed V. The figure shows, by way of example only, a 3x2 arrangement of three vertically arranged and two horizontally arranged lower package trays 61; other arrangements are possible. The film 162 is turned downwards by the labeling arm 120 with the side bearing the indicator label 1 in the transparent area 1620 by the deflection roller 101 and sealed onto the format 161 by the sealing station 110, while a modified atmosphere, such as a nitrogen atmosphere as described above, is introduced into the package. As a result, the indicator label is positioned within the package 6 and comes into contact with this atmosphere.

[0085] The optical sensor 180 can then be used to measure the presence or concentration of gaseous components, such as oxygen, or other analytes, such as decomposition products like ammonia or hydrogen sulfide, in this atmosphere, which indicate the progression of deterioration or spoilage of the packaged goods. Even a single row of sensors, as shown in FIG. 7, can monitor the modified atmosphere created within the package 160. If two optical sensors 180 are present in each lane, one at the front and one at the back of the conveying direction V (two parallel lanes are shown here, capable of handling nx2 packaging configurations), a post-sealing leak test can be performed, in which the composition of the atmosphere is measured, and then the packaging configuration 161 is exposed to a rapidly changing external atmospheric pressure immediately after sealing, and any changes in the composition of the atmosphere within the package, such as an increase in oxygen content, are measured. Packages in which significant changes are detected can be rejected after separation (mechanical separation of the individual packages 6 of the configuration 161) or, if the leak is not severe, can be given individual expiration dates, usually shortened. [Explanation of symbols]

[0086] 1 indicator label 1' Semi-processed indicator label 2. Indicator substance part / zone / layer 2a, 2b Thickened end region 2c Thickened longitudinal end region 2 1,1' carrier layer 4. Adhesive layer 1,1' 5 Peel layer 10 Indicator label tape 10' Semi-finished Indicator Label Tape 11 Label section 12 Surplus 30 10,10' tape carrier layer 40 10,10' tape adhesive layer 50 10,10' peel layer 6 Packaging 61 Lower 62 Upper film 620 Transparent area within 62 63 Sealed end connecting 61 and 62 7 Package contents 8 Optical Sensor L light field 100 packaging machine 110 Sealing Station 120 Adhesive Arm 121 120 tip 122 Deflecting roller 130 Optical detection means V speed y1,y2 120 y / pitch axis z1,z2 120 z / yaw axis 160 sealed packages 161 A form consisting of multiple small areas arranged in a grid pattern 162 Cover Film Transparent area in 1620 162 Optical sensor for detecting and measuring 180 1

Claims

1. 1. An indicator label for the determination of an analyte in a multi-component fluid mixture, in particular for the determination of the concentration of said analyte, comprising: a carrier layer (3); an adhesive layer (4) evenly applied to the lower surface of the carrier layer (3); an indicator substance portion (2) on an upper surface side of the carrier layer (3) opposite to the lower surface side, the indicator substance portion (2) containing an indicator substance that indicates the presence of the analyte, in particular enables the concentration thereof to be measured by optical detection means, in particular by excitation of the indicator substance by excitation light and reading of the fluorescence emitted by the indicator substance; An indicator label, characterized in that the indicator substance portion (2) has a uniform thickness, i.e. extends uniformly in a direction perpendicular to the upper surface of the carrier layer (3).

2. The indicator substance portion (2) have a relative thickness deviation of less than 10%, in particular less than 1%, and / or having an absolute thickness between 5 micrometers and 500 micrometers, in particular between 10 micrometers and 100 micrometers; The indicator label of claim 1.

3. The carrier layer (3) made of cellulose or plastic, in particular polypropylene or polyester, and / or having a thickness between 20 micrometers and 1000 micrometers, in particular between 50 and 200 micrometers; The indicator label according to claim 1 or claim 2.

4. The adhesive layer (4) comprises a food-compatible adhesive and / or a vegan adhesive, The indicator label according to any one of claims 1 to 3.

5. the indicator substance portion (2) is elongated in shape, with a length to width ratio between 2 and 20, preferably between 5 and 10, in particular the indicator substance portion (2) is a substantially rectangular strip with a width between 0.5 and 2 mm, preferably 1 mm, and a length between 4 and 12 mm, preferably 7 or 8 mm; The indicator label according to any one of claims 1 to 4.

6. the indicator substance portion (2) is flush with the carrier layer (3) at one location, preferably at two locations, in particular at two opposite locations; The indicator label according to any one of claims 1 to 5.

7. the adhesive layer (4) has a thickness between 10 and 200 micrometers, in particular between 50 and 100 micrometers; The indicator label according to any one of claims 1 to 6.

8. is substantially transparent to visible light and preferably also colorless; The indicator label according to any one of claims 1 to 7.

9. the indicator substance of the indicator substance portion (2) is a luminescent dye, in particular a fluorescent dye, at least one luminescence parameter, such as relative intensity, excitation frequency, emission frequency and / or decay time, varies continuously depending on the presence of the analyte, in particular depending on the concentration of the analyte, so that the presence, in particular the concentration of the analyte, can be deduced from the luminescence parameter measured by the optical means (8); The indicator label according to any one of claims 1 to 8.

10. A method for producing the indicator label according to any one of claims 1 to 9, comprising: a) providing or producing a label blank (1') comprising a carrier layer (3) with an adhesive layer (4) applied to its underside; b) printing an indicator substance portion (2) containing an indicator substance on an upper surface side of the carrier layer (3) opposite to the lower surface side.

11. the blank label (1') comprises a label portion (11) adjacent to or surrounded by an excess portion (12), the indicator substance portion (2) is printed in step b) so that one, preferably two, particularly two opposite end regions of the indicator substance portion (2) are located on the excess portion (12) of the blank label (1'), and in the next step c) the excess portion (12) is removed. The method of claim 10.

12. An indicator label tape comprising a plurality of indicator labels (1) according to any one of claims 1 to 10, the indicator labels being attached in a row one after the other on a tape-like release layer (50), the release layer (50) being made of or coated with a material capable of lightly adhering the adhesive layer (4) of the indicator labels (1), in particular a plastic with fluorinated end groups.

13. A method for manufacturing the indicator label tape according to claim 12, comprising the steps of: i) preparing or making a tape from a tape-like adhesive layer (40) between an upper tape-like carrier layer (30) and a lower tape-like release layer (50); ii) the following two steps: dividing at least the carrier layer (30) and preferably the adhesive layer (40) into a plurality of label portions (11) arranged one after the other in a row and at least one excess portion (12) adjacent to or surrounding the label portion (11), in particular by punching or cutting the carrier layer (30) and preferably the adhesive layer (40); a step of printing indicator substance portions on the label portion (11) and the at least one excess portion (12) before or after the dividing step, in such a way that one, preferably two, particularly two opposite end regions of the indicator substance portion (2) are located on the at least one excess portion (12) and the remaining portion of the indicator substance portion (2) is located on the label portion (11), respectively; The two steps consist of iii) removing, in particular peeling off, said at least one excess portion (12); A manufacturing method comprising:

14. 10. A packaging for food or other sensitive items, in particular a MAP packaging filled with a modified atmosphere, characterized in that an indicator label (1) according to any one of claims 1 to 9 is adhered to an area (620) that is sufficiently transparent to excitation light and fluorescence.

15. The package (6) comprises a flat or dish-shaped lower part (61) closed at least in part by a film (62) that is transparent to the excitation light and the fluorescence, and the indicator label (1) is adhered to the side of the film (62) that is in contact with the atmosphere inside the package (6) in the region (620) of the film (62) that is transparent to the excitation light and the fluorescence.

15. The package of claim 14.

16. The area (620) to which the indicator label (1) is adhered is also provided with a printed matter, and the printed matter is sufficiently transparent to the excitation light and the fluorescent light. The package according to claim 14 or claim 15.

17. An ink that is transparent to the excitation light and the fluorescence is used to prepare the printed matter.

17. The package of claim 16.

18. In the area covered by the indicator label (1), the printed matter has a printed area and a non-printed area, and the non-printed area occupies at least 5%, preferably at least 10%, in particular at least 25% of the area of ​​the indicator label.

18. The package according to claim 16 or claim 17.

19. the printed matter is a grid of raster dots applied by digital printing, and the distance between adjacent dots of the grid is between 1.05 and 1.5 times the radius of the raster dots; 19. The package of claim 18.

20. A packaging machine for packaging food or other delicate items in packages according to any one of claims 14 to 19, wherein the packages pass through the packaging machine in a conveying direction at a conveying speed (V), A packaging machine comprising a labeling means (120) for attaching the indicator label (1) to an arbitrarily designated suitable position (1620) inside the packaging body (6) that comes into contact with the atmosphere inside the packaging body after sealing the packaging body, so that the indicator label (1) is optically visible from the outside.

21. at least one optical sensor (180) for measuring at least one gaseous component of the atmosphere inside the package produced and sealed by the packaging machine (100), the optical sensor (180) being aligned at the appropriate position (1620) in accordance with a specification also used by the labeling means (120), the specification being in particular the distance from a predetermined reference point or line of an individual package, of a multi-package form (161) or of another packaging part, in particular of the top cover foil (162); 21. The packaging machine of claim 20.

22. The optical sensor (180) manually or automatically aligned laterally relative to the side edge of the sealed package; After alignment, scanning the indicator label passing through the field of view of said optical sensor; optically measuring the recognized indicator label (1) to determine the gas component; In particular, it is provided to report if the expected indicator label (1) is absent or insufficiently legible; 22. The packaging machine of claim 21.

23. detection means (130) for dynamically recognizing and detecting the position of the transparent areas (1620) of the individual not-yet-sealed packaging forms or packaging parts (161, 162); said labelling means (120) being provided to apply said indicator label (1) in the area detected by said optical detection means (130); and / or said optical sensor (180) is adapted to be automatically aligned with said detected position and is mounted on a lateral carriage specifically for this purpose; The packaging machine according to any one of claims 20 to 22.

24. 16. A method for packaging food or other sensitive items in a package according to claim 14 or claim 15, and subsequently controlling the quality of the modified atmosphere within said package by optical measurement of at least one gaseous component of said modified atmosphere, comprising the steps of: a) applying an indicator label (1) according to any one of claims 1 to 9 to an unsealed package (6) using a labeling means (120) in a designated sufficiently transparent area (620, 1620) on the inside of the package (6) that will be in contact with the atmosphere inside the package (6) after sealing, by changing the position of the labeling means (120) as needed; b) using an optical sensor (180) manually or automatically aligned with said arbitrarily designated area (1620), i. scanning the indicator label (1) passing through the detection area of ​​said optical sensor (180); ii. Optically measuring the detected indicator label (1); and In particular, if a supposed indicator label is not present, i.e. if no indicator label is detected on one of said packages within a known time window corresponding to said sufficiently transparent area (620, 1620) passing through the detection field of said optical sensor (180), a warning signal is output, after which the affected package is preferably marked physically or visually. method.

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