JPH0277647A - Controlling method of food freshness by allowable temperature and time - Google Patents

Abstract

PURPOSE:To judge freshness of a food considerably simply and correctly by calculating the freshness of said food having various histories of temperature and time in an environment to be controlled, by an differential operation system. CONSTITUTION:Control of freshness is managed in a constitution that is comprised of a personal computer 1, a CRT 2, a keyboard 3, a printer 4, a temperature indicating recording meter 5, a thermocouple 6, a freezer 7, a refrigerator 8, an air conditioning chamber 9, an extension board 10, a bar code printer 11, a bar code reader 12, a hand-held radiating thermometer 13, a hand-held psychrometer 14, an infrared moisture meter 15 of electronic scale type and a freshness measuring device. While values of various times indicating the freshness of a food, e.g., taste, color, smell, touching sense which are changing relatively to time and temperature are corrected with the use of a known formula, the freshness of the food is carefully calculated generally in real time in consideration of the change in temperature of the environment where the food is placed, so that the temperature and freshness of the food can be supervised at all times so as not to exceed a predetermined limit.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention is a food freshness method that can be used in an extremely wide range of fields from production to distribution to consumption for foods whose freshness changes depending on temperature and time. This relates to a management method based on the allowable temperature and time.

[Conventional technology]

Including fresh foods such as fish, vegetables, fruits, and milk drinks,
For many processed foods, it is important to maintain and control food freshness at each stage of production, distribution, and consumption.

In general, the freshness of food is affected by its storage temperature and storage period. For example, in the case of fish, the transportation time and environmental temperature after being caught by a fishing boat and transported to the landing port, and the handling environment at the local market after landing. , transportation status to the central wholesale market, distribution from the consignee's auction through middlemen to retail stores, temperature and time history in showcases at retail stores, storage status in refrigerators etc. after reaching consumers. The freshness of food changes depending on how it is handled in the kitchen, at the dining table, and how it is left. In addition, in the case of processed foods, procurement of raw materials, storage status, individual retention status and processing status at manufacturing plants, storage status of intermediate products and products, assortment, temporary storage and logistics status for shipping, etc. Freshness changes depending on storage temperature and period. The same applies to the food service industry such as restaurants and school lunches.

The relationship between storage temperature and storage period for various foods can be determined empirically, by sensory tests such as gloss, color, and aroma, by chemical methods such as nitric value (Note 1), and by methods such as electrical resistance. Determined by physical methods etc.
The relationship between how many days it lasts at what degree Celsius, in other words, the allowable temperature time (T, T, T, -Time Temperatu)
re Tolerance) has been reported.

(Note 1) K value (%) = ((HxR+Hx)B ATP+ADP+AMP+
IMP+HxR+Hx)) However, ATP: Adenosine triphosphate ADP: Adenosine diphosphate AMP: Adenosine monophosphate IMF: Inosinic acid HxR: Inosine Hx: Hyboxanthin However, the temperature and time environment in which each food is actually placed are It is rather rare for the same temperature and the same time to pass, and there are differences in time such as things entering the controlled environment early and things leaving later, and the temperature changes over time even in the same place, and food Rather than moving to the same location, it is rather normal to move to multiple locations with different environments.

For example, the internal temperature of a refrigerator in the kitchen differs in summer and winter, and is affected by the frequency of opening and closing, the airtightness of the door, the heat load of stored items, ventilation conditions depending on storage conditions, and the microbially contaminated environment. Even in commercial refrigerated warehouses, the handling of high-mix, low-volume cargo has been increasing in recent years, so the residence time outside the warehouse (in front rooms, elevators, platforms, etc.) can become a problem in terms of freshness control.

[Problem to be solved by the invention]

In contrast to this situation where food temperature and environmental conditions are diversifying, there is still a strong subjective element in determining the freshness of food, and as a result, usage management by freshness, for example, raw food → semi-raw (seared, vinegared, etc.) → Heating (boil, bake → fry)
At present, there is often confusion regarding the classification of freshness-related uses of raw materials.

Traditionally, freshness management was carried out based on the memory and intuition of the person in charge, or through sampling checks, but as the number of people entering and leaving the controlled environment has increased recently, it has become increasingly difficult to control when individual products enter and how they are processed. How fresh is it and when is it served under strict temperature control?
It becomes difficult to manage them one by one. Furthermore, even if you can see it directly, it may be wrapped so that it cannot be checked, or it may be piled up on a pile, making it impossible to check due to time or location.

Also, if the temperature is constant, how long the freshness will be maintained is reported as data, but when the temperature changes over time, in reality, it is necessary to make mental analogies based on various examples of constant temperature. It is all about the best, and there is a risk of going far wrong at times.

Furthermore, even if a problem with freshness occurs, unless the freshness of ingress and egress is constantly monitored in the area in charge of each managed environment, the cause cannot be traced and it will always be a mystery. In the end, users tend to choose quality based solely on the trust of the final supplier.

[Means to solve the problem]

The present invention was made in order to solve the above problem, and uses known relational expressions to evaluate various forms of freshness, such as taste, color, aroma, and texture, which change in relation to temperature and time. The freshness of each target food is carefully calculated in real time, in principle, by following changes in the temperature environment of each target food from time to time, while making adjustments to suit the food. This is a method of constantly monitoring product temperature and freshness to ensure that they do not deviate. Furthermore, when food is brought into or taken out of the environmental area to be managed, it is affixed with labels that can identify the food as necessary, and through this, freshness can be managed quantitatively and without missing any opportunity, contrary to conventional intuition. This aims to clarify the freshness management system in a practical sense, improve the freshness level, and solve problems.

In other words, the present invention enables food to be kept at the same temperature,
A calculation method that uses differences based on the moment-by-moment changes in the environmental temperature of the food, by assigning initial setting conditions such as product temperature, freshness, storage location, etc. to each food group with a time history, and until the food is completely removed from the environment. The system calculates the temperature and freshness of a food group, displays the calculated values of temperature and freshness, or attaches a display label to the food, and manages the freshness of the food based on the allowable temperature time. There is.

In the present invention, the initial setting conditions may be given by estimation or measurement, and the freshness may be calculated as relative freshness without giving an initial setting and may be set later, and the display may be printed or displayed on a screen. , any display method may be used as long as it can be displayed.

The relational expression used in the calculation method that is the basis of the present invention must indicate freshness.

Below, we will first exemplify that a relational expression between temperature and time for freshness generally exists within a practical range, and then explain a method for calculating freshness by following moment-by-moment changes in salinity.

1. Relational expression between temperature and time for freshness and its example First,
In order for the method according to the present invention to be effective, although the concept of food "freshness" is extremely complex and diverse depending on the item and purpose, it is necessary to It is necessary to be able to manage the temperature and time according to the law of relation between temperature and time and with an accuracy that can withstand practical use.

For this verification, we will rely on the following two publicly known materials. In other words, Table 1 shows examples of citations from two internationally famous documents regarding the shelf life of foods. Column A of Table 0 shows the shelf life of frozen foods (shelf life based on storage temperature, i.e., allowable temperature time). The historical trigger for the standard distribution temperature of frozen foods to be O"F, that is, below -18℃, was the sensory evaluation of the permissible temperature and time of frozen foods by the USA Department of Agriculture's Western Regional Research Institute and the Pasadena Research Institute. Based on the test data from 1948 for 10 years, the data shows that the food can be eaten within this storage period (from Kawabata, Kasuga, member "Practical Food Hygiene", Chuoho Publishing), Table 1. Bll is a representative document that indicates the approximate shelf life of mainly chilled products in the secondary market, and is excerpted from the ASHRAHHANDBOOK (1982 edition, USA) that corresponds to Column A of Table 1 ( This document is also used by the Ministry of Health and Welfare as guidance material for grocery stores and the restaurant industry.)

The present inventor attempted to apply Arrhenius law as the basic relationship between temperature and time. However, the freshness of food encompasses a variety of conceptual phenomena such as the following.

゛40 It is not based on individual chemical reactions, but on the whole, and is based on human sensory evaluation.

There are fundamental differences in the types of mouths, animals, plants, etc.

C. There are systematic differences in the state of life and death as living organisms.

26 There are differences between individuals.

E. It is affected by the presence or absence of microbial contamination.

There are differences in individual local environmental conditions (micrometeorological conditions such as temperature, humidity, carbon dioxide concentration, convection, radiation, etc.).

Differences in purpose of use as food (ingredients) lead to differences in freshness evaluation standards.

Therefore, in order to facilitate a comprehensive explanation, the inventor employed the following method.

For example, the freshness of food comes first (fresh vegetables and fruits at the time of harvest, fresh fish at the time of fishing, fresh meat at the time of slaughter, processed foods at the time of manufacturing, and foods that require aging at the time of production). Let's assume that it is 100% (at the end, etc.), and that it gradually deteriorates and drops to 0%. That is, it is assumed that the freshness of the food is initially 100 and gradually decreases to 0 according to the Arrhenius law as shown in the following equation (1). However, the temperature of the food shall be constant.

F(t) =F(0)exp(-kt): (1)k
-＾exp(-B/RT): (2) However, F(t): Freshness at time t (%) F(0): Initial freshness (%) k: Reaction rate constant A: Constant depending on the item (1/ ) E: Activation energy by item (cal/s+ol)
R: Gas constant - 1,986 cal/"K-mol)T
: Absolute temperature (°K) If you want to display it as starting from 0% and deteriorating to 100%, replace F(t) with 100-F(t),
The following equation (1) is used instead of equation (1).

F(t)=100- (100-F(0)) exp
(-kt): (1)' In the equation (1), two types of freshness can be considered depending on how the "initial" freshness, that is, F(0) is taken. In other words, when harvesting vegetables,
As in the production of processed foods, the absolute standard for food is 100%, so to speak, absolute freshness is the percentage compared to 100%, and relative freshness is the percentage when the food reaches a certain state. An initial value of 100% can be considered as relative freshness, which is a percentage compared to the initial value of 100%.

If equation (1) holds as a freshness relationship, then
From equation (1), F(t) is proportional to F(0), so
Even if the absolute freshness of F(0) is not known, F(t) can be expressed as a percentage of F(0), such as relative freshness such as α% of F(0). Therefore, for example, if the freshness F(t) after a time is found to be β% as an absolute freshness by analyzing the values, then the absolute freshness of F(0) is It is determined that β÷α×100%. This means that as long as the temperature and time history are known, freshness can be traced back in the past from later analysis results. For example, if the relative freshness is α% of the first, then β%, and then 1% of the relative freshness, and the analysis result is δ% of the absolute freshness, the initial absolute freshness is δ + (αβr) It can be calculated as 10'%.

The limit for food consumption (Note 1) for general fish, chicken, pork, etc. is approximately 60%. In addition, raw food such as sashimi is 20%, and usually 10%.
It is up to about %. Therefore, since the storage period data in column A of Table 1 is from the perspective of edible period,
The value is equivalent to 60% starting from 0%, so the starting value is 10%.
Assume that the data corresponds to 40% of freshness starting from 0%. Same (The data for B451I in Table 1 is recommended as a guideline from the perspective of market distribution of perishable products, so it is equivalent to 10% in K value, and 90% in terms of freshness starting from 100%. Let's consider it as.

Then, the relational expressions corresponding to columns Aa and B are (1), respectively.
Both equations (1) become the following equations (A) and (B).

40=100exp(-kt): (A)90=10
0exp (kt): (B) Squid, octopus, etc., which self-decompose quickly after death, start from a high value such as 25%, but start from 100%, which can normally be eaten raw. In terms of freshness, if it is normally eaten raw, it should correspond to 90%, or
If the value is within the edible limit for cooking and eating, set it to 4.
It is sufficient to correspond to 0%, and the range may be divided into A, B, C ranks, etc. as appropriate. That is, correspondingly, K
If you convert the value to freshness starting from 100%, you will be able to trade more fairly without knowing each value as a value.

Table 2 shows the constants of A and H using simultaneous equations by substituting the storage period and absolute temperature T into equations (A) and (2) from the data of Aa -12°C and -23°C in Table 1. First find it, then use the found constant ASE to do the following (A).

From the formula, calculate the number of storage days t at 18℃ in column A, and from the formula (B), calculate the number of storage days t at 18℃.
The number of storage days t at the temperature (near 0° C.) in the column is estimated and calculated. That is, t = In(100/40)/(Aexp(-E/RT
)) : (A)'t =In(100/90)/(A
exp(-E/RT)) : (B)' Looking at the results in column A of Table 2, the number of days calculated based on the Arrhenius rule and assuming freshness of 40% for various foods is different from the values in the literature in column A of Table 1. It can be seen that they match relatively well. The results in Column B of Table 2 show that, excluding peaches, raspberries, strawberries, asparagus, Brussels sprouts, cauliflower, pumpkins, etc., the constants calculated from Column A of Table 2 have a two-digit difference in storage days. Despite this, I often find myself losing.

This seems to be because the data in column A for peaches is peeled and sliced. Raspberries and strawberries are used for jam in Europe and the United States, and as the days pass, the raspberries and strawberries break down and become soft.
This seems to be the reason why it is used early because of the texture of the grains. Asparagus, Brussels sprouts, and cauliflower are living organisms that breathe, so this may be due to the difference in their appearance.
If so, it can be handled by changing the calculation formula for frozen and non-frozen states. This appears to be because pumpkins have thick skins that protect them. Sensory comparison shows that once peeled, it lasts about a week at around 10°C. By the way, squash is a type of pumpkin, but its skin is relatively thin and has a calculated shape.

From the above, it can be seen that the calculation of freshness using the Arrhenius law as an example is valid for fresh foods within an accuracy range that can be used practically.

Next, we will explain that moisture, odors, etc. can be treated using the Arrhenius law.

When following the Arrhenius law, the storage period t is calculated using formula (A) or (B
), it is inversely proportional to the reaction rate constant k, that is, it is inversely proportional to the constant A and exp(-E/RT).

Table 3 is a table comparing the saturated steam table and exp(-E/RT).

30° from 0°C when Table 3 E is 10656 cal/mol
They match up to C (at 100°C there is an error of about 20%). This means that if the relative humidity is constant, between 0°C and 30°C, if the relative humidity is α% and the saturated water vapor pressure is p, there is room for evaporation by p(1-α). In other words, it evaporates in proportion to the saturated water vapor pressure. Therefore, the Arrhenius constant is determined by temperature and humidity. Using a similar approach, volatile components such as odors can also be calculated. The amount of volatilization at the same temperature depends on the constant A. The amount of remaining volatile components can be determined by subtracting the amount of volatile components from time to time. However, if the surface is in a relatively dry state and enters a high humidity environment, it will absorb moisture until it reaches equilibrium, so this only applies in a relatively low humidity environment. The same is true.

What the main term means is that if the Arrhenius constant E related to freshness is exactly 10,656 cal/sol, then the amount of water that is lost through evaporation from moment to moment corresponds to the amount of deterioration in freshness of the food. Become.

Therefore, if you measure the moisture content, there is no need to worry about the imbalance between the moisture in the center and the moisture in the surface layer (for example, if the material is thin, or the moisture permeates into the surface layer faster than the evaporation rate). When the problem is only the moisture on the surface of the object or surface layer,
etc.), it is theoretically possible to calculate freshness.

If the moisture % at time t is expressed as W (t), initial moisture W (0), and final moisture W (ω), the Arrhenius constant is set as Aw SEw = 10656 cal/sol instead of A and H, and temperature and humidity are expressed as follows: If (r%) is constant, W(t) = $1(00) + (W(0) −W(o
o)) ・exp(-Aw ・(100-r) ・ex
p(-Ew/RT) ・t) or W(t) −W((X)) = (W(0) −W(■
)) ・exp(-Aw ・(100-r) ・exp
(-1J/RT) t): (3) Taking the ratio of equation (1) into which equation (2) is substituted, the following equation (C) is obtained.

F(t)bar(t) -W((X)))-F(0)bar(0)-%1((X)))'Xexp(-A-exp
(IE/RT) ・t) +exp, (-Ah ・(1
00-r) ・exp(-〇w/RT) ・t):
(C) That is, if the Arrhenius law calculation based on the constant ASE and the calculation using the constant A-1E- are performed in parallel, freshness starting from 100% can be made to correspond to moisture.

In addition, microbial contamination naturally affects freshness, including the value of food, but if the calculated freshness value and the actual freshness value (sampled value) differ by more than individual differences or variations in the local environment, microbial contamination may occur. There is a suspicion that
This can be an indirect check.

■ Calculation of freshness following temperature changes To calculate freshness when the temperature changes, if the absolute temperature of the product is T when following the Arrhenius law, the following equations (1) and (4) Equation, (4) Equation is obtained.

F(t)=F(0)exp (-Ajexp(f!/R
T) dt) : (4) F(t) = 100-(10
0-F(0) ) exp (-A S exp(-E
/RT)dt) : (4)' That is, equation (4) is a general form of freshness starting from 100%. In addition, in formula (4), instead of F(t), the value is expressed as K(t), K(t) = 100 (100-K(0)) e
xp (-A j exp(-E/RT)dt)'
:(4)'' is the general form of the K value.For moisture, instead of equation (3), the following equation becomes - boat fishing.

W(t) −W(oo) = (W(0) −W(oo
)) exp(-8--S (100-r(t)) ・e
xp(-Ew/RT) ・dt) : (3)' However, A-2 Arrhenius constant of water evaporation depending on food, shape, etc. Ew: Same as above r(t): Relative humidity at time t Therefore, equation (4) and If equation (3) is calculated in parallel, it becomes possible to correlate freshness and moisture.

If the freshness deterioration rate V in -a can be expressed as the following formula with food temperature as θ, then the amount of freshness deterioration V(θ)Δt from time t to time 1Δt
is subtracted from the freshness at time t, F(t+Δt) =F(t)−v(θ)Δt: (5)'
and replace FCt+Δt) with new F(t),
Thereafter, if the calculation of equation (5) is repeated from time to time using the product temperature θ at that time, the freshness F(t) at time t will be approximately determined.

Even if the relationship between various temperatures on the deterioration rate is given as a table, if the above equation (5) is found by interpolation or extrapolation, freshness can be calculated for any relationship, not just the Arrhenius law. Become. That is, this is possible if the relationship between temperature and time is known for the target temperature range.

Regarding food temperature, the transient temperature generally differs depending on the location of the food, such as the surface or center. However, due to the nature of food, it is not possible to measure the temperature of all food items, so it is necessary to estimate the food temperature at the target location to be managed from the surrounding environmental temperature and sampled food temperature values.

The target position here refers to average product temperature, surface product temperature (temperature rises quickly in high temperature environments, which means it is easy to deteriorate)
, the center temperature (it is the least likely to cool down in low-temperature environments, meaning it is most likely to deteriorate), and the position depending on the purpose of use (for example, the back muscles are sampled for fish value analysis), etc.

For example, the moment-by-moment average product temperature can be calculated approximately as follows. First, heat transfer while no phase change such as freezing or thawing (thawing) has occurred is based on the following equations (6) to (9) assuming an average product temperature θP of the food P.

From equations (6) and (7), Δθp=Uap ・Ap(θA(t)−〇P(t))Δ
t/Wp −cp: (8) Then, new θP(t) = previous θP(t) + Δθp: (9) However, AQ (t)−: Between time t and t+Δt, Δ from environment A is transferred to food. Amount of heat transferred to P per unit time (Kcal/H) θA(t): Temperature of environment A at time t (°C) cp(t)
: Temperature of food P at time t (°C) Uap : Overall heat transfer coefficient (Kcal/(nf HH・"C)) Two types: non-frozen and frozen Ap: Area surrounding food p (rrf) - p: Weight of food P (K-g) Cp: Specific heat of food P (Kcal/(Kg ・"C)) Two types: unfrozen and frozen, and phase changes such as freezing and thawing (thawing). During this period, latent heat is absorbed, and the product temperature does not change during that time (cp(t) = freezing temperature). Therefore, the above equation (7) can be transformed into the following equations (10) and (11). It changes like this.

New w+=previous value+Δw'<Wp: (11)
However, L: latent heat (kcal/kg) 1: weight of phase change (kg) Q: heat received due to phase change. Equation (9) is the continuous cp( t) "Freezing temperature: (12) When following the Arrhenius law, for example, the value and moisture (volatile components can also be applied) are expressed as follows: ``The value at time t is K(t), and the moisture is W(t).'' ), T = 273 + θp(t)
As ``K'', differentiate equations (4) and (3) and get ΔK(t) = (100-K(t)) ・A-exp
(-E/RT) ・Δt: (13) New K(t) = Previous K(t) + ΔK(t) : (1
4) ΔW(t) = −(W(t) −W((X)))
・8-・(100-r(t))・exp(-t!w/
RT) ・Δt: (15) New enemy (t) = previous direct t) + Δbeast t”): (16) is obtained.

However, ΔK(t): % change in value between time t and t+Δt
ΔW(t): % change in moisture between time t and t+Δt
Beast ω): Final moisture % The surrounding environment is not constant, for example, from above due to convection, from the bottom due to heat conduction, from the front and back due to radiation from heat sources and cold sources, from the left and right due to contact with objects and due to heat conduction. Such,
Heat is absorbed differently in each direction: top and bottom, front and back, and left and right. If we divide the boundary surrounding P into n places, we can calculate the heat balance around P by dividing it into (-1) for each boundary instead of using equation (6), and instead of equation (7), we can use .Equations (17) and (18) can also be applied mutatis mutandis when dividing the inside of a food to determine the temperature of each part.

〔Example〕

FIG. 1 is a block diagram of an apparatus that implements the method of managing food freshness based on permissible temperature and time according to the present invention.

In this figure, reference numeral 1 is a personal computer that calculates and manages product temperature and freshness, and a CRT 2, a keyboard 3, and a printer 4 are connected to this personal computer 1. Further, a six-point temperature indicator recorder 5 is connected to the personal computer 1, and six of the six-point temperature indicator recorders 5 are installed in each of the freezer 7, refrigerator 8, and air-conditioned room 9. 0 thermocouple 6...
・6 is connected.

Furthermore, a barcode printer 11 and a barcode reader 12 are connected to the personal computer 1 via an expansion board 10 , and the barcode printer 11 reads the product name,
Manufacture date, entry (or exit) time, signs that can be identified for management purposes such as storage location, and freshness value at the time of entry (or exit) are printed, and the barcode reader 12 reads them at the time of entry, moves around the facility, It is used for identification when hot water is tapped and during sampling analysis. Reference numeral 13 is a portable radiation thermometer that measures the initial temperature of the product without contact and inputs it into the personal computer 1 using the keyboard 3 as an initial condition.

Further, reference numeral 14 is a portable thermohygrometer, reference numeral 15 is an electronic balance type infrared moisture meter, and reference numeral 16 is a freshness measuring device for measuring the value of animal meat.

Next, a procedure for managing food freshness based on permissible temperature and time using the above-mentioned apparatus will be explained based on FIG. 2.

First, read the signs or set the initial conditions.
This is to make it possible to identify foods by sorting them by storage location, etc. From now on, this sign will be used when verifying when hot water is discharged from the management area, when moving within the premises, when correcting past data or data on existing food in the premises based on sampling analysis results, or when revising data on existing food in the premises. Used when tracking problems. For example, if the food is entered in pallets, a unique sign is attached to the pallet (for example, a barcode indicating a unique address attached to the center digit of the pallet), and the unique sign corresponds to the food placed on the pallet. The freshness of the food is controlled by dividing the food little by little until it runs out of hot water. If the handling unit is a cardboard case, a label may be attached to the cardboard case, and if it is a pack unit, a label may be attached to each bag to identify the food. Zero or more may be combined. Heat balance data includes overall heat transfer coefficient, heat transfer area,
Freshness data such as weight and specific heat are A if according to Arrhenius law.
,, As a general rule, store them in advance using constants such as E (.

Next, after ST2, where labels have been written if necessary, the surface of the food (used for calculation as the initial product temperature) is measured using a portable radiation thermometer 13. While considering the following, priority is given to items with the highest rate of freshness deterioration, such as foods exposed to high temperatures, so it is determined whether it is time to calculate the food.If Sr1゜ is YES, the environmental temperature and humidity are , measure the product temperature, Sr5, calculate the product temperature (time elapsed from last time to this time Δt → heat balance ΔQp → product temperature change Δθp → current product temperature θp - previous product temperature θp + Δθp), and calculate Sr7, and freshness. Calculate (average of previous and current product temperatures → freshness deterioration rate V at that temperature → freshness deterioration ΔF = -V・Δt → current freshness F-
Previous freshness F + ΔF) Sr1゜When calculating the evaporated moisture moment by moment and making it correspond to the moisture % analysis value,
The calculations of equations (15) and (16) are performed in parallel in addition to Sr1. If Sr1 is NO, the process returns to ST4 after performing other calculations in ST6. After ST8 above, determine if it is outside the target freshness range and Sr9; if NO, proceed to Sr6 unless there is an instruction to move inside or outside the venue; if YES, issue a warning 5T
IO0STII is used when food is moved within the facility or taken out of the facility.When moving food within the facility, the correspondence between the sign and the storage location must be changed.
When distributing food in portions outside the facility, calculate the remaining quantity and perform the following operations on the food to be dispensed. In other words, in 5T12, which measures the surface of the hot water when it is tapped, and in 5T13 and 5T14, which writes or prints a sign if necessary, the sampling data obtained by sampling and measuring freshness or temperature inside and outside the facility is input, and this data is statistically processed and determined as necessary. Correct the heat balance data and freshness data accordingly5.
T15. Then, it is determined whether all the food is outside the store and 5T16
, if YES, the process ends; if NO, the process returns to Sr1.

Next, in order to monitor a large number of foods with high precision, we change the calculation timing according to the rate of deterioration of each individual food item. A method of calculating items with a slower temperature, that is, items with a lower temperature, using a longer time interval will be explained based on FIG. 3.

First, the temperature θi (t) of each point i (i=1.2...n) in the current environment is measured 5T21, and then the calculation results for each management target tpO1tpL θp(tpl), ΔFp,
αP(θp).

Read ΔθMAX -P 5T22 (P=1.2.3
...m).

However, tpo: previous calculation time tp of target part p to be managed
l: Latest calculation time θp(tp
l) : Product temperature (°C) Δ of target part P to be managed at the same time
Fp: Freshness deterioration (%) of target part P to be managed from time tpO to tpl αP (θp): Temperature gradient of freshness deterioration rate at temperature θp of target part P to be managed (%・5ec-'・"C -')
ΔθMAX −p: θ related to the target part P to be managed
1 (1) Highest temperature rise (°C) ΔθMA
X −p=MAX (θi (t)−θ1(t−T))
However, θ1(t)>θp Next, 5T23 (P=1.2...m) calculates the next calculation time tp2 for each managed object as follows.

tp2=tpl+EP/ (ΔFp/(tpl tp
o) + Mp) However, Ep: Allowable freshness error (%) of target part p to be managed Mp:
αP(θp)・ΔθtX −pHowever, it is set to zero when the temperature decreases.

Then, if the next calculation time tp2 is rearranged from earliest to lowest, 5T24°, that is, from 5T23, P=1.2, ・
...Apply m, and if it is from 5T27, apply only j.

Next, the object of the earliest next calculation time tp2 that has been sorted in 5T24, that is, the earliest management object (this is set as j)
5T25, it is determined whether the next cycle T of the timing check has arrived, and if YES, it is determined whether there is a target to be managed.5T2B, If this is YES, proceed to 5T21; if NO, the process ends. Also 5T26
is NO, the next calculation time tj2 of the managed target J is no longer
5T27゜tj2-tjl+Ej/ (ΔFj/(tjl-tjO
))' The following describes the results of an experiment in which freshness was calculated using the foods shown in Table 2, using the constant ASE calculated values of the foods also shown in Table 2, and assuming that the food complies with Arrhenius law. However, regarding mackerel, Affil! Since the data does not specify fatty fish and fish species, the inventors experimentally determined A (= 46086) and E (= 7072).
) calculations were also used.

As mentioned above, Table 1 shows the storage period based on sensory evaluation, so originally the freshness should be evaluated using the same criteria. However, that was 30 years ago, so it is virtually impossible, and it will be difficult to verify by sensory evaluation. Therefore, we decided to use the K value for animal meat and the water content for plant meat as measurable measures of freshness. 13) and (14) were decided to be used. Originally, equations (15) and (16) should be used for moisture, but in this case, the ASE constant is used as is for moisture, and an approximate formula adjusted by the final moisture value W ((X)) is used. I decided to take a method.

In other words, as seen in Table 3, E and Ew (=1065
The difference in evaporation amount based on the difference between
Various temperatures (room temperature, chilled temperature, frozen temperature) are tested under 60% environmental conditions (excluding temporary transient conditions such as when changing locations, on a steady basis on the evaporation side). And (15
) The final moisture value W ((X)) in the equation is approximately determined by a preliminary experiment at the same room temperature and humidity for the same length of time, based on the case where the test is kept at the highest room temperature for the longest time. In other words, the final moisture value W derived from equation (3)
The following equation (19) to calculate (Co): −(ω)=(enemy(t) −W(0)
Jw) : (19) However, Jw-exp(-Aw ・(100-r) ・exp(
−Ew/RT) ・Instead of t), the pseudo final moisture value W
・(ω) is expressed as the following equation (20), −・(■)=(Ka(t) −W (0) X J)÷(
1-J): (20) However, J = exp (-A-exp (-E/RT) ・t) is determined in advance using the experiment initial moisture value W (0) and the experiment final moisture value W (t). .

Note that if the initial moisture at the time of harvest is Ws, the freshness F(t) after t hours and the initial freshness value F (0) are F(t) - (Ws
-W(t)) / (Ws-t(ω)) x 100F
(0) = (Ws-%1(0)) / (Ws-1(Q
))) X 100: (21) If we set the following, we can obtain the same form as equation (4). In other words, the moisture % and the freshness % correspond approximately on a one-to-one basis.

Similarly, for octopus, squid, etc. whose value does not start from 0%, it is possible to correspond to the freshness from 100% to 0%, making it easy to understand when used for boat fishing. Moreover, when expressed in terms of relative freshness based on the initial value, the following equation is obtained, where W(0) is used instead of Ws.

p(t)=(W(0)-w(t))/(ga(0)
-1・(ω))xlooo: (21)' The items to be tested are 1° mackerel, 2° mackerel, and 2° mackerel in order from the top of Table 2.
．． Strawberry, 3. Beef loin, 4. Pork loin, 5. Chicken fillet, 6. Asparagus, 7. Peace, 8. I selected 8 items of spinach, and the values were 1.3.4.5. , moisture is 2.6.7.8. We analyzed the initial value at the start, the final value, and the sampled values during the process.

Methods for measuring K values include the simple column method, which belongs to the separation analysis method, the enzymatic method, which belongs to the coexistence analysis method, the colorimetric method, and the biosensor. 0 analysis using a method of measuring both using test paper (freshness measurement kit and freshness test paper manufactured by Environmental Analysis Center Co., Ltd.) includes 3. ~5. is the fleshy part, 1. The muscular part of the back of the mackerel was used.

The moisture content was measured using a commercially available infrared moisture analyzer (FD-220°, automatic detection of drying end point, moisture % display type, manufactured by Kett Kagaku Kenkyusho Co., Ltd.).

For each of 1 to 8, 9 test areas (■ to ■) were set up and placed in the freezer (
-14 to -17°C1 Average -15°C1 Humidity 45 to 75
%, average 60%), refrigerator (0-4℃, average 2℃1 humidity 40-85%, average 55%), air-conditioned room (17-25℃)
C1 average 22℃, humidity 40-55%, average 50%) 3
Each test plot was set at a fixed or almost fixed time (1
We conducted a two-day experiment in which we moved the cells every 6 hours).

Each test section for each item weighs 3 to 7 g (mackerel cut on the back side, strawberries cut in half, beef, pork, and poultry cut fleshy part on the seam, asparagus and spinach cut in the middle) cut into two bare specimens with a small heat capacity (one piece is about 4 pieces).
One is for the intermediate analysis after 8 hours (of course, the intermediate analysis results are not used to correct the freshness calculation in this case, and the second is for the final value analysis after about 48 hours). Each test piece is placed in an aluminum foil container so that it does not mix with other test pieces. Furthermore, a barcode label indicating the experiment number was attached to each aluminum foil container (144 in total) using Sellotape. The 32-hour and 48-hour specimens are placed in a Styrofoam box in a freezer and cooled with dry ice while waiting for the value and moisture measurements to be taken on each specimen.

In Table 4, the 0 surface area, which is a constant for heat balance used in the momentary calculation of product temperature, was determined in advance by determining the relationship between weight and surface area depending on the shape, and was approximately calculated from the weight. The overall heat transfer coefficient was determined in a preliminary test using the constants in Table 4 from the temperature rise in the frozen state for air-conditioned rooms and refrigerators, and from the temperature drop in the unfrozen state for the freezer. As a result, the difference in stored value 1 is larger than the difference in items, and the overall heat transfer coefficient is 4 to 18 Kcal/(m” ・hr ・”
It was found that there were variations up to C). Therefore, we determined the storage location for each test area for each item (two test pieces in the same location),
Heat balance calculations were performed using the overall heat transfer coefficient values determined in preliminary tests at that location.

The results are shown in Table 5. It can be seen from the summary in Table 5 that the calculated values correspond to the analyzed actual measured values.

By the way, "relative freshness" using formula (21) is 22°C.
Looking at the strawberries in the test area No. 2, which remained in the equipment for two days, the actual value was 8.
Using 6.3%, F (2 days) = (90,6-86,3) / (9
0,6-43,8)・100=9.2% On the other hand, in equation (4), F (0) = 0 and the same constant A,
If t=2 days in E, the calculated value is 7.1%. In the same way, measured "relative freshness" vs. calculated "relative freshness"
Asparagus: 16.5%: 20.9%, respectively
Piece 20%: 15.7%, Spinach 9.7%:
It becomes 15.7%. Although there is an error of about 5% (which seems to be around this level even if the number of days increases), the general idea is correct.

〔Effect of the invention〕

Since the present invention is configured as described above, the freshness of foods in a controlled environment with various temperature and time histories can be calculated and managed using a differential calculation method, so that the freshness of foods can be determined extremely easily and accurately.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of an apparatus for carrying out an embodiment of the present invention, and FIGS. 2 and 3 are flowcharts showing work procedures. 1...Personal computer 5...Temperature indicator recorder 6...Thermocouple 7...Freezer 8...Refrigerator 9...Air conditioning room Patent applicant Hara Nii Design Co., Ltd. Osamu Fujimaruyo Iwabuchi Person Patent attorney Japan-China political situation 1 person Figure 2

Claims (1)

[Claims] When food is stored in a controlled environment or passed through during the work process, initial conditions regarding product temperature, freshness, storage location, etc. are assigned to each food group that has the same temperature and time history, and the food is stored in the controlled environment. The temperature and freshness of the food group are calculated using a differential calculation method according to the environmental temperature changes of the food from moment to moment until it disappears.
A method for controlling food freshness based on permissible temperature and time, characterized by controlling the freshness of food by displaying a calculated freshness value or attaching a label to the food.