Edible animal temperature estimation system, edible animal temperature estimation program, and edible animal temperature estimation method

Abstract

According to the present invention, the internal temperature of edible animals is appropriately determined.　A freshness evaluation system 1 has a test kit 100 and a server 200 that can communicate with each other via a network N. The test kit 100 has a detector body 11 and a test body 20. The detector body 11 transmits results of temperature detection inside the test body 20 to the server 200. The server 200 holds information about a function representing the relationship between the temperature inside the test body 20 and the temperature inside the meat of the edible animal. The server 200 estimates the temperature inside the meat of the edible animal on the basis of the information and the results of temperature detection inside the test body 20. The server 200 calculates an evaluation value representing the freshness of the meat of the edible animal on the basis of the estimated temperature.

Description

Food animal temperature estimation system, food animal temperature estimation program, and food animal temperature estimation method

[0001] The present invention relates to a temperature estimation system for food-producing animals, a temperature estimation program for food-producing animals, and a temperature estimation method for food-producing animals.

[0002] It is sometimes necessary to measure the internal temperature of food animals in order to understand changes over time in the animals during storage or distribution, such as changes in freshness and maturity. One possible way to measure the internal temperature of food animals is to pierce the sensor of a thermometer into the animal. However, this method is not desirable because it harms the animal. Patent Document 1 relates to a device that estimates and acquires the internal temperature of food animals through simulation based on temperature fluctuations in the actual environment of food animal storage and distribution under certain conditions. This device makes it possible to determine the internal temperature of food animals without harming them.

[0003] Japanese Patent Application Laid-Open No. 2021-139894

[0004] Simulations such as those in Patent Document 1 may have difficulty following temperature fluctuations in the actual environments of storage and distribution of food animals. Therefore, a method for appropriately determining the internal temperature of food animals exposed to the actual environment is desired.

[0005] An object of the present invention is to provide a food animal temperature estimation system, a food animal temperature estimation program, and a food animal temperature estimation method that appropriately grasp the internal temperature of food animals.

[0006] The temperature estimation system according to a first aspect of the present invention is a system for estimating the temperature of an edible animal, and comprises a test subject that is not an edible animal, a detector that detects the temperature inside the test subject, information indicating the relationship between the temperature inside the test subject and the temperature inside the meat of the edible animal, and a calculation device that estimates the temperature inside the meat of the edible animal based on the temperature detection results by the detector, and outputs the estimation result to an output device.

[0007] A temperature estimation program according to a second aspect of the present invention is a program for estimating the temperature of an edible animal, which estimates the temperature inside the meat of the edible animal based on information showing the relationship between the temperature inside a test body other than the edible animal and the temperature inside the meat of the edible animal, and the detection results of the temperature inside the test body, and causes a computer to function as an arithmetic unit that outputs the estimation result to an output device.

[0008] A temperature estimation method according to a third aspect of the present invention is a method for estimating the temperature of an edible animal, in which a computer estimates the temperature inside the meat of the edible animal based on information indicating the relationship between the temperature inside a test body different from the edible animal and the temperature inside the meat of the edible animal, and the detection results of the temperature inside the test body, and outputs the estimation result to an output device.

[0009] According to the first to third aspects of the present invention, the relationship between the temperature inside the test body and the temperature inside the meat is acquired in advance, and information indicating this relationship is used by a calculation device or computer. The calculation device or computer then estimates the temperature inside the meat by comparing the detected temperature inside the test body with the information. Therefore, it is possible to appropriately determine the temperature inside the meat of an edible animal in the actual environment in which the test specimen is placed.

[0010] Here, the test specimen is an object different from the food animal whose temperature is to be measured, and its physical properties, shape, size, etc. do not need to be the same as those of the meat of the food animal. For example, the test specimen may be made of a material with a specific heat capacity that is significantly different from that of meat. In other words, the material, size, shape, etc. of the test specimen are less likely to be restricted by the type of meat of the food animal. Therefore, the present invention allows the test specimen to be configured to be easy to use in accordance with the actual environment.

[0011] The test specimen may be constructed to have similar physical properties, shape, and size to the meat of the target food animal. The "meat" of the present invention includes both meat from aquatic animals and livestock animals.

[0012] In the first aspect of the present invention, it is preferable that the calculation device calculates the estimated value based on one or more functions that represent the relationship between the temperature inside the meat of the food animal and the temperature inside the test body, whereby the temperature inside the meat is appropriately estimated based on the function that represents the relationship between the estimated value of the temperature inside the meat and the temperature inside the test body.

[0013] In the first aspect of the present invention, it is preferable that any one of the one or more functions is a first function consisting of a logarithmic function. By using the first function consisting of a logarithmic function, it becomes possible to appropriately estimate the temperature inside the meat based on the temperature inside the test body.

[0014] In addition, in the first aspect of the present invention, it is preferable that one of the one or more functions is a second function, which is a function such that the estimated value changes at a predetermined ratio for each change in temperature within a predetermined temperature range in the test body, and the calculation device calculates the estimated value based on the second function for temperatures within a predetermined temperature range in the test body, and calculates the estimated value based on the first function for temperatures outside the predetermined temperature range. According to this, within the predetermined temperature range, the meat temperature is appropriately estimated based on the second function, which is a function such that the estimated value changes at a predetermined ratio for each change in temperature within a predetermined temperature range in the test body. Furthermore, outside the predetermined temperature range, the meat temperature is appropriately estimated based on the first function.

[0015] In the first aspect of the present invention, it is preferable that one of the one or more functions is a third function different from both the first function and the second function, and the arithmetic device calculates the estimated value based on at least one of the first function and the second function when the temperature inside the test body drops, and calculates the estimated value based on the third function when the temperature inside the test body rises. In this way, the first function and the second function are used when the temperature of the test body drops, and the third function is used when the temperature of the test body rises, thereby allowing the temperature of the meat to be appropriately estimated.

[0016] In the first aspect of the present invention, the third function is preferably a function in which the temperature inside the meat changes linearly with the temperature inside the test body, thereby making it possible to appropriately estimate the temperature of the meat when the temperature of the test body increases based on the linear function.

[0017] In the first aspect of the present invention, it is preferable that the one or more functions include two or more mutually different functions, and the arithmetic device uses the two or more functions for two or more mutually different temperature ranges related to the temperature inside the test body when calculating the estimated value. In this way, the temperature of the meat can be appropriately estimated by using the function according to the temperature range.

[0018] In addition, in the first aspect of the present invention, it is preferable that the one or more functions include two or more mutually different functions, and the arithmetic device, when calculating the estimated value, uses the two or more functions differently depending on whether the temperature inside the test body is rising or falling. In this way, the temperature of the meat can be appropriately estimated by using the function differently depending on whether the temperature inside the test body is rising or falling.

[0019] In addition, in the first aspect of the present invention, it is preferable that the arithmetic device further calculates an evaluation value representing the freshness of the meat of the food animal based on the result of estimating the temperature inside the meat of the food animal. In this way, the evaluation value is calculated based on an appropriate estimate of the temperature inside the meat, thereby ensuring the reliability of the evaluation value.

[0020] 1 is a schematic diagram showing the configuration of a freshness evaluation system according to one embodiment of the present invention. FIG. 2 is a block diagram showing the functional configuration of the server of FIG. 1. FIG. 3 is a graph showing an example of changes over time in the K value, which is an evaluation value representing freshness calculated by the freshness evaluation system of FIG. 1. FIG. 4 is a flowchart showing an example of the flow of processing executed by the server of FIG. 1. FIG. 5 is a graph showing the relationship between the temperature of a test specimen and the actually measured temperature or calculated temperature of a yellowtail according to one embodiment of the present invention. FIG. 6 is a graph showing the relationship between the temperature of a test specimen and the estimated temperature of a yellowtail according to one embodiment of the present invention.

[0021] A freshness evaluation system 1 according to one embodiment of the present invention will be described below with reference to FIGS. 1 to 4. The freshness evaluation system 1 is for evaluating the freshness of meat from food-producing animals. As an example, when meat from food-producing animals is stored or transported in a refrigerated or frozen state, this system is used to track the freshness of the meat stored or transported in the actual environment. Food animals refer to all edible animals and are not limited to specific species. However, in this embodiment, fish is used as an example. Meat includes both whole animals and parts of animals. Meat also includes seafood and their fillets that have not undergone any processing other than slaughtering, beef or pork carcasses after slaughtering, and whole meat. Furthermore, meat may be processed by cutting, heating, drying, smoking, adding other ingredients such as seasonings, etc. Specific examples of processed meat include minced meat, boiled meat, grilled meat, kamaboko, sausage, bacon, hamburger steak, nuggets, fried chicken, cutlets, and other cooked and semi-cooked foods, as well as pastes.

[0022] As shown in FIG. 1, the freshness evaluation system 1 includes a test kit 100 and a server 200 .

[0023] The test kit 100 is a device for measuring the temperature of meat from food animals, and is used by being placed in the same environment as the meat from the food animal whose temperature is to be measured. The test kit 100 includes a detector body 11 and a test specimen 20. The detector body 11 can be connected to a network N such as the Internet via a built-in communicator or through an information communication terminal such as a smartphone connected to the detector body 11 via short-range wireless communication such as Bluetooth (registered trademark), Wi-Fi (registered trademark), or RFID (Radio Frequency Identification). The detector body 11 communicates with a server 200 through the network N.

[0024] The test kit 100 may be a sealable container or package made of metal, plastic, glass, etc., containing the detector body 11 and the test specimen 20. In this way, when meat such as seafood is stored or transported in water in an aquarium, the test kit 100 can be similarly placed in water and used.

[0025] The detector body 11 is connected to the probe 12. The tip of the probe 12 is installed inside the test piece 20. The probe 12 detects the temperature of the object using any of a thermocouple, a thermistor, a metal resistance thermometer, etc. The detector body 11 has a processor, a memory device, etc., and processes the detection signal from the probe 12. The processing results are acquired as temperature detection values, and these values ​​are stored in the memory device in sequence at predetermined time intervals Δt (e.g., 10 minutes). The detector body 11 transmits the temperature detection values ​​stored in the memory device to the server 200 in the order in which they were acquired.

[0026] The test specimen 20 is an indirect measurement target used instead of directly measuring the temperature of meat from a food animal. For this reason, the test specimen 20 is not made of meat from a food animal itself, but rather is made of a material completely different from meat. For example, considering the transportation of meat, it is preferable to use a material that has as little moisture as possible and is in a stable solid state. From this perspective, as one example, a configuration in which a polymer compound powder is filled into a plastic package may be used.

[0027] An example of the polymer compound may be a water-absorbent polymer. Examples of water-absorbent polymers include polycarboxylic acid (co)polymers such as (meth)acrylic acid (co)polymers and maleic acid (co)polymers, and salts or ester-modified products thereof. Polyhydroxy (co)polymers such as vinyl acetate (co)polymer hydrolyzates and vinyl alcohol (co)polymers, and ester-modified products thereof. Polysulfonic acid (co)polymers such as styrene sulfonic acid (co)polymers, and salts or ester-modified products thereof. Vinylpyrrolidone (co)polymers. Alkylene oxide (co)polymers such as polyethylene glycol and polypropylene glycol. Monosaccharides, polysaccharides, and salts thereof, such as amylose, amylopectin (starch), pectin, dextrin, carrageenan, xanthan gum, galactomannan, glucuronic acid, galacturonic acid, alginic acid, and cellulose. Modified polysaccharides such as carboxymethylcellulose, proteins such as gelatin, and polypeptides containing glutamic acid or aspartic acid, etc., may also be used. These may be chemically copolymerized or mixed as a polymer blend. Alternatively, a mixture of a substance such as a water-absorbing polymer and a liquid such as water may be filled in a package.

[0028] The packaging may be made of thermosetting resins such as vinyl resins, polyurethane resins, and epoxy resins, photocurable resins such as acrylic ester-based photocurable resins, etc. The packaging may also be formed by combining a plurality of resin materials and metal materials such as aluminum by adhesion or thermal melting (so-called lamination), or by performing post-processing such as painting or vapor deposition, or by combining with glass fiber, inorganic fillers, etc.

[0029] In addition to the above, a solid mass made of a material such as plastic or clay that can maintain a three-dimensional shape may be used as the test specimen 20 as is.

[0030] The server 200 (corresponding to the arithmetic device of the present invention) is constructed from hardware such as a CPU (Central Processing Unit), memory devices, and various interfaces, and software such as program data stored in memory. This software can be distributed by downloading via the Internet or by various recording media. The hardware functions as each functional unit based on the software.

[0031] The server 200 has, as such functional units, a memory unit 210, a temperature estimation unit 220, and an evaluation value calculation unit 230 shown in FIG. 2. The memory unit 210 stores detected temperature data 211, estimated temperature data 212, evaluation value data 213, and function data 214. Examples of the detected temperature data 211, estimated temperature data 212, and evaluation value data 213 are shown in Table 1 below. Times t1, t2, etc. represent times that have advanced by Δt from time t0. The detected temperature data 211 indicates the detected temperature values ​​T0, T1, T2, etc. received from the detector main body 11. T0, T1, T2, etc. are the detected temperature values ​​at times t0, t1, t2, etc. The estimated temperature data 212 indicates temperatures U1, U2, etc. inside the meat of an edible animal estimated from the temperatures T0, T1, T2, etc. indicated by the detected temperature data 211. The temperatures U1, U2, ... are estimated values ​​of the temperature inside the meat of the food animal at times t1, t2, .... The evaluation value data 213 indicates evaluation values ​​K1, K2, ... that represent the freshness of the meat of the food animal, calculated from the temperatures U1, U2, ... indicated by the estimated temperature data 212. The evaluation values ​​K1, K2, ... represent the freshness at times t1, t2, ....

[0032] [Table 1]

[0033] The function data 214 is data relating to a function relating the temperature inside the test specimen 20 to the temperature inside the meat of the food animal. The function indicated by the function data 214 is based on actual measured values ​​or calculated temperature values ​​obtained by measuring the temperature inside the meat of the food animal and the test specimen 20 placed in the same environment. Specifically, an approximation function relating to the temperature T inside the test specimen 20, which represents the temperature U inside the meat of the food animal, is obtained using a fitting method such as the nonlinear least squares method or the Nelder-Mead method. There are three types of approximation functions used in this embodiment: approximation functions A, B, and C, shown in the following equations 1 to 3. In the equations, a, b, c, and d are constants. t is time, and decay_rate is a constant greater than 0 and less than 1.

[0034] [Equation 1] (approximation function A) U = a + b * log T

[0035] [Formula 2] (Approximate function B) U(t+Δt)=U(t)*decay_rate

[0036] [Formula 3] (Approximate function C) U=c*T+d

[0037] The temperature estimation unit 220 estimates the temperature inside the meat of the food animal based on the detected temperature data 211 and the function data 214. The estimation method will be described in detail later. The estimation result is stored in the storage unit 210 as estimated temperature data 212.

[0038] The evaluation value calculation unit 230 calculates an evaluation value representing the freshness of meat from a food animal based on the estimated temperature data 212. Examples of such evaluation values ​​include the K value and / or the FI value. The smaller the K value, the higher the freshness, and the larger the FI value, the higher the freshness. These values ​​are based on the decomposition reaction of ATP (adenosine triphosphate) in meat. After the death of a food animal, ATP in its body is sequentially decomposed into ADP (adenosine diphosphate), AMP (adenosine monophosphate), IMP (inosinic acid), AdR (adenosine), HxR (inosine), and Hx (hypoxanthine). As shown in Patent Document 1, the K value and the FI value are calculated as follows using the amounts of these substances present in a unit amount of meat:

[0039] [Formula 4] K value (%) = (HxR amount + Hx amount) / (ATP amount + ADP amount + AMP amount + IMP amount + AdR amount + HxR amount + Hx amount) * 100

[0040] [Formula 5] FI value = {ATP amount - (HxR amount + Hx amount)} / (ATP amount + ADP amount + AMP amount + IMP amount + AdR amount + HxR amount + Hx amount)

[0041] The ATP amount, ADP amount, AMP amount, IMP amount, HxR amount, and Hx amount (hereinafter referred to as ATP amount, etc.) are the amounts of ATP, ADP, AMP, IMP, AdR, HxR, and Hx present per unit amount of meat, respectively. As shown in Patent Document 1, these are calculated using the initial ATP value, postmortem time, and internal temperature in the meat of a food animal. The evaluation value calculation unit 230 calculates the ATP amount, etc. from the estimated temperature indicated by the estimated temperature data 212, the initial value input by the user, and the time of death of the food animal. The evaluation value calculation unit 230 then calculates the K value and / or FI value from the calculated ATP amount, etc. using Equations 4 and 5. The calculation results are stored in the storage unit 210 as evaluation value data 213.

[0042] The server 200 can communicate with the terminal 90 via the network N. The terminal 90 is composed of a PC, a smartphone, or the like, and is equipped with a display (corresponding to the "output device" of the present invention). In response to a request from the terminal 90, the server 200 transmits the estimated temperature indicated by the estimated temperature data 212 and the evaluation value indicated by the evaluation value data 213 to the terminal 90. The terminal 90 displays the estimated temperature and evaluation value transmitted from the server 200 on the display. The display displays the change over time of the estimated temperature and evaluation value as numerical values ​​and graphs. Note that the temperature inside the test specimen 20, the estimated temperature inside the meat, the amount of ATP, etc. may also be displayed on the display together with the change over time of the evaluation value.

[0043] FIG. 3 is an example of a graph showing the change in the K value over time as an example of an estimated temperature and an evaluation value. The example in FIG. 3 includes a period during which meat from food-producing animals is frozen and stored. During this period, the temperature of the meat is sufficiently low, greatly suppressing the decomposition reaction of ATP. Therefore, the K value in FIG. 3 shows almost no change. For this reason, a configuration may be adopted in which the evaluation value calculation unit 230 determines whether or not to calculate the K value depending on whether or not the temperature indicated by the detected temperature data 211 is below a predetermined value (e.g., −10°C). Specifically, when the temperature indicated by the detected temperature data 211 is below the predetermined value, the evaluation value calculation unit 230 may not perform the K value calculation process, and the K value may be maintained constant throughout the period during which the temperature is below the predetermined value.

[0044] The flow of a series of processes performed by the server 200 to calculate an evaluation value using the detected temperature data 211 will be described with reference to FIG.

[0045] First, the detected temperature data 211 stored in the storage unit 210 is read (S1). Next, the server 200 initializes a time reference variable t (S2). The time reference variable t is a parameter indicating which time in the period corresponding to the detected temperature data 211 is to be referenced. In this embodiment, when the start time of the detected temperature data 211 is t0, t is set to t0+Δt.

[0046] Next, the server 200 references the temperatures at time t and time t-Δt indicated by the detected temperature data 211 and determines whether the temperature at time t is lower or higher than the temperature at time t-Δt (S3). If it determines that the temperature is lower (S3, lower), the server 200 determines whether the temperature at time t is equal to or higher than a predetermined value (S4). If it determines that the temperature at time t is equal to or higher than the predetermined value (S4, Yes), the server 200 selects approximate function A from among the functions indicated by the function data 214 stored in the storage unit 210 (S5). On the other hand, if it determines that the temperature at time t is lower than the predetermined value (S4, No), the server 200 selects approximate function B from among the functions indicated by the function data 214 stored in the storage unit 210 (S6). If it determines in S3 that the temperature at time t is higher than the temperature at time t-Δt (S3, higher), the server 200 selects approximate function C from among the functions indicated by the function data 214 stored in the storage unit 210 (S7).

[0047] Next, server 200 estimates the temperature inside the meat of the food animal using one of the functions selected in S5 to S7 (S8). The estimation result is stored in memory unit 210 as estimated temperature data 212. Next, server 200 calculates evaluation values ​​(K value and FI value) that represent the freshness of the meat of the food animal based on the temperature estimated in S8 (S9). The calculation result is stored in memory unit 210 as evaluation value data 213.

[0048] Next, the server 200 assigns t+Δt to the time reference variable t (S10). Next, the server 200 determines whether or not there is data at time t in the detected temperature data 211 (S11). If it is determined that there is more data (Yes in S11), the server 200 executes the process of S3. If it is determined that there is no more data (No in S12), the server 200 ends the series of processes.

[0049] An example of the present invention is described below. In this example, a 5.8 kg yellowtail fish was first stored in ice at 0°C from an internal temperature of 17°C (the seawater temperature at the fishing site) immediately after ikijime (killing). Note that it was difficult to actually measure the internal temperature from 17°C (the internal temperature of the fish immediately after ikijime) to 5.7°C (the internal temperature of the fish when transferred from the ice-filled "dambe" to an ice-filled shipping box) due to the fish's thrashing, which would damage the temperature detector probe. Therefore, the change in internal temperature was calculated based on a one-dimensional heat conduction model. From 5.7°C, the temperature detector probe was inserted into the fish, and the internal temperature of the fish was detected every 10 minutes. Note that the internal temperature corresponds to the temperature at a predetermined position inside the meat. For example, the predetermined position is near the center of the line segment connecting the head and tail of the fish, corresponding to the spine.

[0050] Meanwhile, a water-absorbent polymer, specifically a powder of sodium polyacrylate, enclosed in a plastic package was prepared as the test specimen 20. The probe 12 was inserted into this test specimen 20, and the detector body 11 and the test specimen 20 were enclosed in a sealable package to form a test kit 100. This test kit 100 was immersed in ice so that the temperature detected by the detector body 11 became 17°C. The temperature inside the test specimen 20 was then detected every 10 minutes until the temperature detected by the detector body 11 reached 0°C.

[0051] FIG. 5 is a graph showing the relationship between the temperature of the yellowtail obtained as described above and the temperature T of the test piece 20, based on the elapsed time from the start of temperature detection. The coordinates of each point in FIG. 5 correspond to the temperature of the yellowtail and the temperature of the test piece 20 at the same elapsed time from the start of temperature detection. Then, based on the nonlinear least squares method, fitting was performed using the above-mentioned Equation 1 for all points in FIG. 5. As a result, a in Equation 1 was 8.74 and b was 1.80. In other words, the following Equation 6 was obtained as the approximate function A for the yellowtail. The solid line in FIG. 5 indicates the curve corresponding to Equation 6.

[0052] [Formula 6] U=8.74+1.80*logT

[0053] The coordinates of each point in Figure 6 correspond to the temperature T of the test specimen 20 and the estimated temperature U obtained from that temperature T using Equation 6. The dotted line in Figure 6 indicates a straight line corresponding to U = T. The points within the ellipse in Figure 6 correspond to points within the range where T is equal to or greater than 0°C and less than 3°C. In this range, approximation using the logarithmic function of Equation 6 does not hold. For this reason, in this embodiment, U within this range is expressed by the approximation function B of Equation 2. The decay_rate was obtained based on the actual measured temperature of the yellowtail corresponding to a T less than 3°C. As a result, the decay_rate was approximately 0.906. Furthermore, when fitting using the approximation function A was performed again, excluding points where T was equal to or greater than 0°C and less than 3°C, a in Equation 1 became 8.58 and b became 1.95.

[0054] Next, assuming that a 5.8 kg yellowtail fish was immersed in water at 25°C from an internal temperature of 0.3°C, the change in the yellowtail's internal temperature over time was calculated based on a one-dimensional heat conduction model. Furthermore, test specimen 20 prepared in the same manner as above was immersed in water at 25°C while the temperature detected by detector body 11 was 0.3°C. The temperature inside test specimen 20 was then detected by detector body 11 every 10 minutes. Three values ​​each of the obtained internal yellowtail temperature and test specimen 20 temperature values ​​were extracted from the start time, and these values ​​were fitted using the approximation function C shown in Equation 3 based on the nonlinear least squares method. As a result, c in Equation 3 was 0.195 and d was 0.123.

[0055] Summarizing the above, approximate functions A to C shown in the following formula 7 were obtained. The condition for using approximate function A is that the temperature of the test piece 20 is decreasing and is 3°C or higher. The condition for using approximate function B is that the temperature of the test piece 20 is decreasing and is less than 3°C. The condition for using approximate function C is that the temperature of the test piece 20 is increasing.

[0056] [Formula 7] (Approximate function A) U=8.58+1.95*logT (Approximate function B) U(t+Δt)=U(t)*0.906 (Approximate function C) U=0.195*T+0.123

[0057] To verify the appropriateness of the thus obtained approximate functions A to C for evaluating the freshness of yellowtail, the following experiment was conducted. A 5.8 kg yellowtail (yellowtail) with an internal temperature of 17°C (the seawater temperature at the fishing location) was caught in Hakodate and then ikejime (killed by ikijime) and stored in an ice-covered environment at 0°C. A transport test was then conducted from Hakodate to Tokyo. The ATP degradation products in the flesh of the yellowtail that arrived in Tokyo were measured at an analytical laboratory in accordance with the Japanese Agricultural Standards (JAS0023). Based on these measurements, the K value was calculated using Equation 4, resulting in a result of 10.8%. Meanwhile, the test kit 100 was kept at 17°C, then immersed in ice at 0°C for the same time as during transport. Based on the temperature change, the K value of the yellowtail upon arrival in Tokyo was estimated using the approximate functions A to C shown in Equation 7. The freshness evaluation system 1 calculated the K value, resulting in a result of 11.5%.

[0058] According to the freshness evaluation system 1 of the present embodiment described above, the relationship between the temperature inside the test specimen 20 and the temperature inside the meat of the food animal is acquired in advance, and function data 214 indicating approximate functions A to C as information indicating this relationship is stored in the memory unit 210 of the server 200. The server 200 then estimates the temperature inside the meat from the detected temperature value inside the test specimen 20 and approximate functions A to C. Therefore, it is possible to appropriately determine the temperature inside the meat of the food animal in the actual environment in which the test specimen 20 is placed.

[0059] As described above, the test specimen 20 is an object different from the food animal whose temperature is to be monitored, and its physical properties, shape, size, etc. do not need to be the same as those of the meat of the food animal. For example, the test specimen 20 may be made of a material with a specific heat capacity that is significantly different from that of meat. In other words, the material, size, shape, etc. of the test specimen 20 are less likely to be restricted by the type of meat of the food animal. Therefore, the freshness evaluation system 1 can configure the test specimen 20 to be easy to use depending on the actual environment.

[0060] The above explanation does not mean that the present invention excludes cases in which the test specimen 20 is constructed so as to have similar physical properties, shape, and size to the meat of the target food-producing animal.

[0061] Furthermore, in this embodiment, when the temperature inside the test specimen 20 drops, approximate function A is used if the temperature is equal to or greater than a predetermined value, and approximate function B is used if the temperature is less than the predetermined value. As shown in Equations 1 and 2, approximate function A is a logarithmic function, and approximate function B is a function in which the estimated temperature drops at a constant decay rate (decay_rate). In other words, different approximate functions A and B are used in two temperature ranges, which are divided into two ranges depending on whether the temperature is equal to or greater than a predetermined value. Furthermore, approximate function C is used when the temperature of the test specimen 20 rises. As shown in Equation 3, approximate function C is a linear function in which the estimated temperature U changes linearly with respect to the detected temperature T. In other words, different approximate functions are used depending on whether the temperature is dropping or rising. In this way, by using different approximate functions depending on the temperature range and the temperature change pattern, the temperature of the meat can be appropriately estimated.

[0062] Furthermore, in this embodiment, the evaluation value (K value or FI value) representing the freshness of the meat is calculated based on the temperature of the meat that has been appropriately estimated as described above, thereby ensuring the reliability of the evaluation value.

[0063] <Modifications> The above is a description of a preferred embodiment of the present invention, but the present invention is not limited to the above-described embodiment, and various modifications are possible within the scope described in the means for solving the problems.

[0064] For example, in the above-described embodiment, the server 200 corresponding to the arithmetic device of the present invention transmits the temperature estimate and the evaluation value to the terminal 90 via the network N, and the changes over time in the temperature estimate and the evaluation value are displayed on the display of the terminal 90 corresponding to the output device of the present invention. Alternatively, a single device such as a PC that functions as both the arithmetic device and the output device of the present invention may perform both calculation and output of the temperature estimate and the evaluation value. The temperature estimate and the evaluation value may be output in a manner other than display on a display. For example, the temperature estimate and the evaluation value may be output as audio corresponding to the temperature estimate and the evaluation value, or may be output by printing on printing paper. Furthermore, the temperature estimate and the evaluation value may be output by recording on a recording medium, or may be output by transmission to an external device via the network N.

[0065] Furthermore, in the above-described embodiment, the server 200 stores function data 214 indicating a function that expresses the relationship between the temperature U inside the meat and the temperature T inside the test piece 20. Alternatively, or in addition, the server 200 may store data that indicates a table that expresses the relationship between the temperature U inside the meat and the temperature T inside the test piece 20. The temperature U inside the meat can be obtained by comparing the detection result of the temperature T inside the test piece 20 with this table.

[0066] 1 Freshness evaluation system 11 Detector body 20 Test specimen 100 Test kit 200 Server

Claims

1. A system for estimating the temperature of an edible animal, comprising: a test subject that is not an edible animal; a detector that detects the temperature inside the test subject; and a computing device that estimates the temperature inside the meat of the edible animal based on information indicating the relationship between the temperature inside the test subject and the temperature inside the meat of the edible animal and the temperature detection results by the detector, and outputs the estimated temperature to an output device.

2. The food animal temperature estimation system according to claim 1, characterized in that the computing device calculates the estimated value based on one or more functions that indicate the relationship between the temperature inside the meat of the food animal and the temperature inside the test body.

3. The food animal temperature estimation system according to claim 2, wherein any one of the one or more functions is a first function consisting of a logarithmic function.

4. The temperature estimation system for food animals described in claim 3, characterized in that one of the one or more functions is a second function that causes the estimated value to change at a predetermined ratio for each change in the temperature within a predetermined temperature range in the test body, and the calculation device calculates the estimated value based on the second function for temperatures within a predetermined temperature range in the test body, and calculates the estimated value based on the first function for temperatures outside the predetermined temperature range.

5. The temperature estimation system for food animals described in claim 4, characterized in that any of the one or more functions is a third function different from either the first function or the second function, and the calculation device calculates the estimated value based on at least one of the first function and the second function when the temperature inside the test body drops, and calculates the estimated value based on the third function when the temperature inside the test body rises.

6. The temperature estimation system for food animals according to claim 5, wherein the third function is a function such that the temperature inside the meat changes linearly with the temperature inside the test body.

7. The temperature estimation system for food animals described in claim 2, characterized in that the one or more functions include two or more functions that are different from each other, and the calculation device uses the two or more functions for two or more different temperature ranges related to the temperature inside the test body when calculating the estimated value.

8. The temperature estimation system for food animals described in claim 2, characterized in that the one or more functions include two or more functions that are different from each other, and the calculation device, when calculating the estimated value, uses the two or more functions depending on whether the temperature inside the test body is rising or falling.

9. A temperature estimation system for food animals as described in any one of claims 1 to 8, characterized in that the calculation device further calculates an evaluation value representing the freshness of the meat of the food animal based on the result of estimating the temperature inside the meat of the food animal.

10. A program for estimating the temperature of an edible animal, which estimates the temperature inside the meat of the edible animal based on information showing the relationship between the temperature inside a test body other than the edible animal and the temperature inside the meat of the edible animal, and the detection results of the temperature inside the test body, and causes a computer to function as an arithmetic device that outputs the estimated result to an output device.

11. A method for estimating the temperature of an edible animal, comprising: a computer estimating the temperature inside the meat of the edible animal based on information indicating the relationship between the temperature inside a test body different from the edible animal and the temperature inside the meat of the edible animal, and based on the detection results of the temperature inside the test body, and outputting the estimated result to an output device.

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