JP2024021877A - Food preservation method, food transport method, and food transporter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method of preservation and packaging for importing, exporting and moving objects that can reduce a risk of food spoilage while also reducing a risk of food freezing in the process.

SOLUTION: An example of a preservation method according to one embodiment of the present disclosure is a method for preserving at least one kind or one form of food, the method comprising: (1) a storage preparation step of preparing a storage equipped with a storage chamber and an electric field forming unit for forming an electric field in the storage chamber; (2) a food packaging step of forming a food package by covering the food with a packaging material and then performing a process for increasing a degree of vacuum inside the packaging material, or preparing the formed food package; and (3) an electric field cooling process for storing the food package in the storage chamber, forming an electric field in the storage chamber and cooling the storage chamber, thereby keeping at least a part of the food in a chilled state.

SELECTED DRAWING: Figure 2

COPYRIGHT: (C)2024,JPO&INPIT

Description

Embodiments of the present disclosure relate to food storage methods, food storage devices, and food transporters.

In recent years, demand for fresh foods (hereinafter collectively referred to as "food") has been increasing worldwide, and unfrozen products are in high demand due to their high added value. Technology that maintains freshness for a long time while maintaining similar conditions is attracting attention. For example, Patent Document 1 describes a freezer using electric field technology that includes a storage container in which food is held, electrodes arranged inside the storage container, and a power source that applies voltage to the electrodes. This freezer is configured so that an electrostatic field is formed inside the storage by applying a voltage from a power source.

JP2001-204428A

By the way, in order to maintain the freshness of foods, it is important to suppress the growth of bacteria in foods that cause spoilage. To this end, it is considered to be particularly important to maintain a state in which the number of bacteria is as low as possible immediately after production. Efforts to utilize such electric field technology are being proposed or explored.

On the other hand, the effect of preserving food freshness (best before date) using electric field technology is closely related to the storage temperature of the food, and the food must be stored in a temperature range below freezing (below 0°C) as much as possible without freezing. It is presumed that storage contributes to suppressing the increase in the number of bacteria over time.

However, the longer the transportation time, such as long-distance sea transportation, the greater the possibility that the commercial value of the food product will be damaged. For example, in order to maximize the freshness preservation effect, if you try to maintain the temperature as low as possible without freezing, external factors such as outside temperature, individual differences in food, the number of days it takes to transport (the longer it is, the more likely it is to freeze), (e.g., the amount of food loaded), the food may become frozen or nearly frozen, which may damage the original product value of the food. In other words, conventional food storage and transportation technology using electric field technology has the disadvantage that it is difficult to reliably maintain an unfrozen state.

On the other hand, if the food is managed at a conservative (relatively high) temperature range with little risk of freezing, the number of bacteria in the food will be relatively high even if the food can be transported without spoiling or freezing. This shortens the expiration date. When this happens, businesses that sell the food in the country of import have no choice but to refreeze such products and distribute them as frozen products. Even in this case, the original commercial value of the food is damaged, and it also leads to problems such as the generation of freezing costs, the generation of greenhouse gases due to the freezing process, and, in some cases, the generation of food waste (food loss). Therefore, the reality is that conventional food storage and transportation technology using electric field technology has not yet been fully put into practical use.

Therefore, the present invention has been made in view of the above circumstances, and aims to maximize the effect of preserving the freshness of food by maintaining it in a chilled state or a state close to it, thereby reducing the risk of food spoilage. An object of the present invention is to provide a food storage method, a food transportation method, and a food transporter that can reduce the risk of food freezing.

An example of a food storage method according to an embodiment of the present disclosure is a method for storing at least one type or type of food, which includes: (1) a storage chamber; and an electric field for forming an electric field in the storage chamber; and (2) forming a food package by covering the food with a packaging material and then performing a process to increase the degree of vacuum inside the packaging material. or a food packaging step of preparing the formed food package; (3) accommodating the food package in the housing chamber, forming an electric field in the housing chamber, and cooling the housing chamber; and an electric field cooling step of maintaining at least a portion of the food in a chilled state.

Moreover, an example of the food transportation method according to an embodiment of the present disclosure uses the food storage method according to the present disclosure, and transports the food while performing the electric field cooling step.

Furthermore, an example of a food transporter according to an embodiment of the present disclosure includes at least one type or one form of food and is transported, and includes a storage chamber and an electric field for forming an electric field in the storage chamber. The storage chamber includes an electric field forming section and a food package formed by covering the food and increasing the degree of vacuum inside, and an electric field is formed in the storage chamber in which the food package is accommodated. and at least a portion of the food is kept in a chilled state with the inside of the storage chamber being cooled.

FIG. 1 is a perspective view showing a schematic configuration of an example of a storage shed according to an embodiment of the present disclosure. 2 is a sectional view taken along line II-II in FIG. 1. FIG. 2 is a sectional view taken along line III-III in FIG. 1. FIG. FIG. 2 is a flow diagram showing an example of a procedure for accommodating and storing a food package in a storage warehouse according to an embodiment of the present disclosure, and transporting the food package in that state.

Hereinafter, embodiments according to an example of the present disclosure will be described with reference to the drawings. However, the embodiments described below are merely examples, and are not intended to exclude the application of various modifications and techniques not explicitly described below. That is, an example of the present disclosure can be implemented with various modifications without departing from the spirit thereof. In addition, any other embodiments that can be obtained by a person skilled in the art based on the embodiments of the present disclosure without requiring any creative action are included in the protection scope of the present disclosure. Further, in the present disclosure, for example, one "process", "step", "part", "body", "chamber", "device", "machine", "vessel", "means", "mechanism", " system, and some or all of the functions and configurations thereof may be realized by two or more of them, or two or more of them may be realized by one.

[Example of configuration of storage space and food transporter used for food storage]
FIG. 1 is a perspective view showing a schematic configuration of an example of a storage warehouse according to an embodiment of the present disclosure, FIG. 2 is a sectional view taken along line II-II in FIG. 1, and FIG. 1. This is a cross-sectional structure taken along line III-III in No. 1. In FIGS. 1 to 3, for convenience of explanation, vertical directions are indicated by arrows Z1 and Z2, and horizontal directions are indicated by arrows X and Y.

The container 10 (housing) has a function of storing food in a cooled state, and may be used as a fixed container, or as a transportation (moving) container for transporting food in a cooled state. can. Examples of fixed containers include those that are installed indoors in food processing plants and buildings, and those that function as warehouses themselves. In addition, examples of the shipping container include containers for marine transportation that are loaded onto ships, containers that are loaded onto moving bodies such as airplanes, vehicles, and the like.

As shown in FIG. 1, the container 10 includes a main body 20 that can accommodate food therein. The main body 20 has a box 40 formed in a rectangular box shape with an opening on the front, and a pair of doors 50 that close the opening on the front of the box 40. The box body 40 and the door portion 50 are made of a metal material such as aluminum or stainless steel, and are electrically grounded.

Further, as shown in FIG. 2, the space surrounded by the inner surfaces of the box body 40 and the door portion 50 is an internal space of the main body 20, and a food package housed in an outer container B such as a cardboard box A storage chamber S10 having a multi-stage structure is defined in which F is stored. Furthermore, a heat insulating material is embedded inside each of the box body 40 and the door part 50 to suppress heat transfer from the storage chamber S10 to the outside of the container 10 in order to improve the cooling performance of the container 10. . Furthermore, the pair of door sections 50 shown in FIG. 1 are connected to the box body 40 so as to be openable and closable. In the container 10, by opening and closing the door portion 50, it is possible to take food packages F into and out of the storage chamber S10. Further, by closing the door portion 50, the storage chamber S10 becomes a closed space, and the inside of the storage chamber S10 and the food package F accommodated therein are maintained in a cooled state.

On the other hand, as shown in FIG. 3, the container 10 further includes a cooling device 30 built in, for example, the back of the main body 20. The cooling device 30 is connected to a power source (not shown) provided inside or outside the storage main body 20, is driven by the power supply, and cools the storage chamber S10 by supplying cold air to the inside. Specifically, the cooling device 30 has an inlet 31 and an outlet 32 that open into the storage chamber S10. The cooling device 30 sucks air in the storage chamber S10 through the suction port 31, cools the sucked air, and blows it out from the blow-off port 32 into the storage chamber S10, thereby cooling the inside of the storage chamber S10. . In this way, the container 10 of this embodiment is a so-called reefer container in which the temperature within the storage chamber S10 can be adjusted by the cooling device 30.

Further, as shown in FIGS. 2 and 3, the container 10 further includes an electric field forming section 60 disposed near the inside of the upper wall section 41 of the storage main body 20. The electric field forming section 60 includes an insulating member 61 and an electrode member 62 connected to the power source (not shown). Thereby, the electric field forming unit 60 is driven by the power supply and forms an electric field inside the storage chamber S10. Further, one end and the other end in the left-right direction X of the electric field forming part 60 are placed on placing parts 81 and 82 provided above the side walls 42 and 43 of the storage main body 20, respectively, and It extends in the depth direction Y.

The types of these mounting parts 81 and 82 are not particularly limited, and may be made of an electrically insulating material (for example, resin) or a conductive material such as iron or stainless steel. Furthermore, the placing parts 81 and 82 have parts 810 and 820 fixed to the side walls 42 and 43, respectively, and parts 811 and 821 on which one end part of the electric field forming part 60 is placed, Both are configured as so-called L-shaped angle members whose X-direction cross sections are L-shaped.

In addition, the "food" included in the food package F is not particularly limited, and includes, for example, meat such as beef and pork, seafood such as fish and shellfish, chicken eggs, fish eggs, dairy products such as milk and cheese, and flour. Examples include noodles made from grain powder such as buckwheat flour, fruits such as strawberries and apples, vegetables such as cabbage and tomatoes, and processed foods thereof. Among these, animal foods such as meat such as beef and pork, seafood such as fish and shellfish, dairy products such as chicken eggs, fish eggs, and milk and cheese are particularly in need of freshness retention effects during long-term storage and transportation. It is suitable as a target to be included in the food package F housed in the container 10 according to the present disclosure.

Furthermore, the food package F is one in which at least one type or one form of the food is covered with a packaging material having heat shrinkability and high vacuum properties (see FIG. 2). Note that the "form" of the food here includes, for example, that even if the food is of the same type, the property, shape, production area, production period, vacuum shrink wrapping state, etc. are different. Moreover, "packaging material" is a type of vacuum pack (packing material) for food. A preferred example of a food package F covered with such a "packaging material" is one formed by covering a food product with a packaging material containing a heat-shrinkable film and vacuum shrink-wrapping the food. In addition, regarding the wrapping state of the food package F, it is not necessary that all of the same type of food necessarily have the same wrapping state, and each of the same type of food may have a different wrapping state. .

In addition, "vacuum shrink wrapping" refers to heating the packaging material while reducing the pressure (vacuum) inside the packaging material containing the food, or in a reduced pressure (vacuum) environment. This is a method of sealing and wrapping the food by shrinking it. Here, the "heat-shrinkable film" included in the packaging material is not particularly limited, and has a shrinkage rate of 1-70% at a heat-shrinking temperature (for example, 70-110°C), and has a predetermined tensile elasticity. Examples include films having a certain ratio. Further, the heat-shrinkable film may or may not be stretched. Furthermore, as the type of heat-shrinkable film, more specifically, films made of known thermoplastic resins can be used, such as polyethylene, polypropylene, polyester, ethylene-vinyl acetate copolymer, polyethylene succinate, polybutylene succinate, Examples include polyvinyl chloride, polystyrene, high impact polystyrene (HIPS), and the like. Furthermore, various additives such as appropriate pigments, fillers, dyes, heat stabilizers, antioxidants, plasticizers, and antistatic agents may be added to the resin constituting the heat-shrinkable film. Furthermore, the packaging material here may be a composite film in which a heat-shrinkable film and a non-heat-shrinkable film are laminated. This non-heat-shrinkable film is also not particularly limited, as long as it has a lower heat-shrinkage rate at the same temperature than the heat-shrinkable film used in combination, for example, heating at 70 to 110°C. Examples include those having a thermal shrinkage rate of less than 1%.

[Example of implementation procedure for food storage method and food transportation method]
FIG. 4 is a flowchart showing an example of a procedure for accommodating and storing the food package F in the container 10 shown in FIGS. 1 and 2 and transporting the food package F in this state.

In step SP1, in order to accommodate the food packages F in the storage chamber S10 of the container 10, the container 10 shown in FIGS. 1 and 2 is installed at a loading location for the food packages F (accommodation preparation step). ). Before or after that, or in parallel, in step SP2, a food package F having high vacuum properties is formed by covering the food with a packaging material containing a heat-shrinkable film and performing vacuum shrink wrapping. Alternatively, the food packaging body F thus formed is transferred to the vicinity of its loading (loading) location (food packaging process).

Next, in step SP3, the food package F is stored inside the storage chamber S10. At this time, the food package F can be held at an appropriate location inside the storage chamber S10. For example, as shown in FIG. A location suitable for cooling and temperature control of the food package F can be selected. Next, in step SP4, a predetermined high voltage is applied from a power source (not shown) to the electrode member 62 of the electric field forming section 60 to form an electric field inside the storage chamber S10. At this time, the high voltage applied to the electrode member 62 may be, for example, an alternating current (alternating current) voltage whose magnitude and direction change periodically as time passes, or a It may be a constant (DC) voltage that does not change the direction of the sheath. The voltage applied to the electrode member 62 can be set to any level, but is set to a high voltage of, for example, several hundred volts to several tens of thousands of volts. Further, the frequency of the alternating voltage applied to the electrode member 62 can be set to any frequency. Note that when the high voltage applied to the electrode member 62 is an alternating current (AC) voltage, the applied voltage can be expressed as an effective voltage. Before or after that, or in parallel, in step SP5, a predetermined power is supplied from a power source (not shown) to the cooling device 30 to supply cold air to the inside of the storage chamber S10. The inside is cooled so that at least a portion of the food inside the food package F is on the verge of freezing (chilled state), and this state is maintained. Note that at least a portion of food refers to at least a portion of one food, or at least one of a plurality of foods. In addition, the state on the verge of freezing includes, for example, a state that is half-frozen or half-thawed, a state where the surface is slightly hardened, or a state where the surface is not completely frozen but is one step away from freezing, such as a dent of 1 mm to 2 mm when pressed with your finger. (initial stage of thawing), etc. Steps SP3, SP4, and SP5 constitute an "electric field cooling step."

Then, in step SP6, an electric field is formed inside the storage chamber S10 as described above, and the container 10 is loaded onto a moving object such as a ship, an airplane, a vehicle, or a railway, while the inside of the storage chamber S10 is cooled. (load) and transport to the destination. As shown in FIG. 2, the container 10 in which the food package F is housed inside the storage chamber S10 and is in a cooled state is a "food transporter" of the present disclosure, including the food package F. This corresponds to an example.

According to the food storage method, food transport method, and food transporter using the container 10 configured as described above, food can be vacuum shrink-wrapped with a packaging material having heat shrinkability and high vacuum properties as a food package F. By maintaining the food in an electric field environment, the non-freezing temperature of the food can be further lowered compared to cases where vacuum shrink wrapping is not performed (e.g., deaerated packs, non-shrink vacuum packs, etc.). This further reduction in the non-freezing temperature is due to the effect of the electric field environment, and in the case of vacuum shrink wrapping, the amount of air that comes into contact with the food and the amount of moisture in the air are reduced, so the freezing point of water (0°C) is reduced. One of the factors is presumed to be that freezing itself becomes more difficult to occur (however, the effect is not limited to this). This allows food to be kept more stably in a chilled state without freezing, further suppressing the growth of bacteria in food that causes spoilage and preserving the freshness of food over a long period of time. becomes possible.

As described above, according to the present disclosure, the risk of food spoilage and the risk of freezing can be reduced, so the edible period of food can be extended more than when vacuum shrink wrapping is not performed. Therefore, we are now able to implement completely new initiatives that were previously impossible to achieve, such as transporting fresh foods that were previously transported by air from distant production areas by sea, and transporting foods that were previously frozen in a chilled state. The transportation method becomes feasible. Furthermore, these allow food to be distributed for a long period of time, thereby reducing the amount of wasted food (food loss) and contributing to the stable supply of food to consumers at low prices. Further, it is possible to prevent a decrease in work efficiency and yield due to thawing work that is required when food is frozen. Moreover, by switching from air transport to sea transport, which has lower logistics costs, it is possible to significantly reduce food procurement prices, and also contribute to reducing _CO2 gas emissions from transport. Can be done. Furthermore, by starting step SP3, step SP4, or step SP5 shown in FIG. 4 after a predetermined time has elapsed from the time of food production, it is also possible to intentionally ripen the food before starting storage or transportation. be. Note that the product may be aged after transportation.

To be more specific about this point, for example, at present, some foreign meat and liquid eggs have low procurement prices and high quality that are highly competitive due to the balance of supply and demand, but transport A major issue was that refrigerated transport was the only way to export to countries over long distances. On the other hand, according to the present disclosure, it is possible to carry out chilled transportation for a long period of time, so there is a great advantage that this problem can be solved. In addition, for example, seafood such as semi-dressed salmon (with only the internal organs removed) is currently being transported by air in a Styrofoam container packed with ice. In contrast, according to the present disclosure, it is possible to transport for a long time while maintaining freshness in a chilled state at a lower temperature than normal transport, which will stimulate new demand and improve product competitiveness. can be significantly increased.

[Modification 1]
As described above, according to the present disclosure, it is possible to transport food by keeping it fresh for a long period of time, and therefore, food can be kept for a long time in an electric field environment that produces lactic acid bacteria while suppressing food spoilage. It is possible. Furthermore, since it is possible to preserve food for a long period of time while maintaining its freshness, that is, it is possible to extend the edible period, it is also possible to increase the amount of free glutamic acid in the food. As a result, it is possible to improve the flavor of the food by increasing the amount of free glutamic acid in the food, and to further delay the progress of spoilage by increasing the number of lactic acid bacteria in the food. In other words, according to the present disclosure, food can be stored and transported in a low temperature zone where bacteria that cause food spoilage other than lactic acid bacteria cannot be active, thereby increasing the proportion of lactic acid bacteria among such common bacteria. This can enhance the effect of maintaining food freshness.

From this point of view, it is preferable that the electric field cooling step (storage or transportation in the state in which it has been carried out) consisting of steps SP3, SP4, and SP5 is carried out for at least one day as modification 1. It is more preferable to carry out the process for a week or more, and it is particularly preferable to carry out the process for several months (for example, 1 month or 2 months) or more. A suitable upper limit for this implementation period can be set as appropriate in consideration of supply timing based on supply and demand balance, transportation distance, season, etc.

[Modification 2]
As a second modification, step SP3 (accommodating the food package F in the storage chamber S10), step SP4 (formation of an electric field in the storage chamber S10), or step SP5 (cooling in the storage chamber) is replaced with food production (slaughter). It is effective to start the process immediately after (or slaughter processing, etc., and nerve tightening, live tightening, or ice tightening processing, etc.) or within a predetermined time from the time of food production. The predetermined time is preferably set to 5 days, preferably 48 hours, more preferably 24 hours, and particularly preferably 1 hour. Note that the preferable lower limit of the period up to this start may vary depending on the time from the production of the food to the end of step SP2 (formation or preparation of the food package F). With this configuration, it is possible to suppress a rapid increase in the number of bacteria in a relatively short period of time immediately after food production, and it is possible to reduce the initial value of the number of bacteria at the start of cooling and holding such food. Therefore, the long-term freshness retention effect can be further enhanced.

[Modification 3]
When the cooling device 30 is built in, for example, the back of the main body 20 like the container 10, the internal space of the storage chamber S10 is cooled to a uniform temperature due to external factors such as the external temperature and the performance of the insulation material. This is actually difficult, and variations in cooling temperature may occur within the storage chamber S10. Further, due to differences in the type and form of food, the temperature at which a suitable chilled state can be achieved may also differ.

Therefore, as a third modification, the food package F is not housed in the storage chamber S10 (for example, prior to actual storage or transportation of the food package F), or the food package F is stored in the storage chamber S10. The temperature distribution inside the storage chamber S10 is calculated when an electric field is formed in the storage chamber S10 (step SP4) and the inside of the storage chamber S10 is cooled (step SP5) while the storage chamber S10 is housed in the storage chamber S10 (during step SP3). You may carry out the temperature measurement process of measuring. Then, the storage position of the food package F in the storage chamber S10 is determined based on the temperature distribution in the storage chamber S10 measured in the temperature measurement step and the type or form of the food packaged in the food package F. (optimization). In this case, temperature sensors may be installed at multiple locations on the inner wall of the storage chamber S10 or on the shelf board as shown in FIG. 2, or temperature sensors may be installed at positions where the spatial temperature distribution within the storage chamber S10 can be measured. It can be arranged three-dimensionally. Further, a data logger or the like may be provided inside or outside the container 10 to collect temperature measurements by these temperature sensors.

With this configuration, if the temperature measurement process is performed in advance, the actual temperature distribution (variation) in the storage chamber S10 can be predicted, so a suitable chilled state can be set depending on the type and form of the food. The desired food package F can be placed at a location that exhibits an achievable temperature. In other words, by utilizing the temperature variations within the storage chamber S10, it is possible to mix and load various types and forms of foods in the same container 10 at a suitable cooling temperature. In this case, the temperature sensor and data logger may remain installed during actual storage and transportation of the food package F, or may be removed. On the other hand, when the temperature measurement process is carried out during the actual storage or transportation of the food package F, the historical data of temperature distribution during storage and transportation is acquired, and subsequent operations and adjustment of product delivery timing, as well as necessary The output of the cooling device 30 can be adjusted accordingly.

[Modification 4]
As a fifth modification, in the electric field cooling step, it is preferable that a medium (such as water) that increases the cooling temperature of the food is not placed in the storage chamber S10. For example, if the suitable cooling temperature for food is - (minus) several degrees Celsius or lower, ice (freezing point: 0°C) or snow ice (freezing point: The inventors have confirmed that when the food package F comes into contact with temperatures such as -1° C., the transition from the chilled state to the frozen state is likely to occur. The reason for this is thought to be that the amount of moisture around the food increases, making it easier for ice crystals, which triggers the release of supercooling, to adhere to the food surface. Therefore, it is desirable that the food package F is not brought into contact with the cold pack.

[Modification 5]
As a fifth modification, when the container 10 is loaded onto a moving body such as a ship and transported to the destination in step SP6 shown in FIG. 4, the food inside the food package F becomes hard due to freezing. It may happen. If the food becomes hard, you can defrost it to a better state (once It is possible to return it to a state close to chilled (not frozen). This is because food cells are less likely to be destroyed when frozen in an electric field environment, and also because food cells are less likely to be destroyed during the thawing process when thawed in an electric field environment. Note that the predetermined temperature may be below the freezing point or may be a temperature higher than the freezing point. The timing of electric field decompression does not have to be before arrival at the destination. In addition, by defrosting with an electric field, a high-quality chilled state can be quickly reproduced.

(Examples 1 to 14)
As a food product, raw pork shoulder loin, which is commercially available at multiple stores, is used, and packaging materials containing heat-shrinkable film (for example, "CT304" manufactured by Sealed Air Japan LLC, "Multibag" manufactured by Multivac Co., Ltd.) are used. By covering the food with a film made by Cryovac, Inc.) and vacuum shrink-wrapping it with a wrapping device (for example, "Turbovac" made by Hirai Company, Ltd., a vacuum packaging machine made by Furukawa Seisakusho Co., Ltd.), the food is A specimen as package F was formed. This specimen is housed in a storage chamber of a container having the same configuration as the container 10, a voltage of 7000 V is applied to the electrode member to form an electric field, and the inside of the storage chamber is kept cooled for a predetermined period of time. I took it out. Immediately after taking out the sample, the sample was pressed with finger pressure, and the degree of freezing of the food used was observed from the amount of dent in the sample at that time. The food storage conditions for each example (cooling temperature setting in the storage chamber, number of storage days, sample weight, packaging type, sample installation location, number of samples installed, and average temperature measurement value at the installation location) and observation results are shown. 1 and Table 2.

(Comparative Examples 1 to 9)
Instead of the packaging materials used in Examples 1 to 14, a packaging material (for example, "Hilaminar NXS" manufactured by Krylon Kasei Co., Ltd.) is used to vacuum non-shrink with a wrapping machine (for example, a vacuum packaging machine manufactured by Furukawa Seisakusho Co., Ltd.). The degree of freezing of the food was observed in the same manner as in Examples 1 to 14, except that the specimen was formed by wrapping. The food storage conditions for each comparative example (cooling temperature setting in the storage chamber, number of days of storage, sample weight, packaging type, sample installation location, number of samples installed, and average temperature measurement at the installation location) and observation results are shown. They are summarized in 3.

In addition, in Tables 1 to 3, the meanings of "(1) to (3)" indicating the specimen installation location and the legends "〇, △, ×" indicating the observation results are as follows.
Location (1): Middle section in the center of the containment chamber Location (2): Lower section on the cooling device 30 side of the containment chamber Location (3): Middle section on the cooling device 30 side of the containment chamber Observation results: dents of 2 mm or more - complete Non-frozen (chilled) state Observation result △: Dent of 1 mm or more and less than 2 mm Observation result ×: Less than 1 mm to completely frozen state

From the observation results shown in Tables 1 to 3, according to the food storage methods of Examples 1 to 14 according to the configuration of the present disclosure, although there is a temperature distribution in the storage chamber, the storage period is from 10 days to about 30 days. It was confirmed that at least part or all of the sample food was maintained in a chilled state at a temperature in the storage room of about -4°C to -5°C, without completely freezing. On the other hand, according to the food storage methods of Comparative Examples 1 to 9, although there is a temperature distribution in the storage chamber, the temperature in the storage room is about -4°C to -5°C during the storage period of 14 days to about 30 days. It was confirmed that the sample food was completely frozen or almost frozen. From these results, it is understood that the food storage method according to the present disclosure can significantly lower the non-freezing temperature of food in an electric field environment.

(Comparative Examples 10 and 11 and Examples 15 and 16)
A plurality of raw pork shoulder loin meats and raw pork belly meats were prepared, and first, the number of bacteria (general viable bacterial count) was measured immediately after slaughtering them. Next, as Comparative Examples 10 and 11, a plurality of raw pork shoulder loin meats and raw pork belly meats were arbitrarily selected, and these sample groups were placed in a packaging material containing a heat-shrinkable film (for example, manufactured by Sealed Air Japan LLC). ``CT304'' manufactured by Multivac, ``Multivac'' manufactured by Cryovac, Inc.), and wrapped with wrapping equipment (for example, ``Turbovac'' manufactured by Hirai Company, Ltd., vacuum manufactured by Furukawa Seisakusho Co., Ltd.). A plurality of specimens as food packaging bodies F were formed by vacuum shrink wrapping using a packaging machine. These specimens were then stored for a predetermined period of time in a 0°C environment in a frozen warehouse that does not have an electric field environment (non-electric field environment), and the number of bacteria (general viable bacteria count) was measured again immediately after storage.

In addition, as Examples 15 and 16, a sample group different from Comparative Examples 10 and 11 was selected, and these samples were stored in a storage chamber of a container having the same configuration as container 10 instead of the above-mentioned frozen warehouse. , the number of bacteria was determined in the same manner as Comparative Examples 10 and 11, except that a voltage of 7000 V was applied to the electrode member to form an electric field, and the storage chamber was kept cooled to -3.2°C for a predetermined period of time. (general viable bacteria count) was measured again.

These food storage conditions and changes in bacterial counts are summarized in Table 4. From these results, in Comparative Examples 10 and 11, in which the specimens were vacuum shrink-wrapped but stored in a non-electric field environment, the number of bacteria after storage was about 10 ⁵ times that of the specimens immediately after slaughter in all parts of the specimens. On the other hand, in Examples 15 and 16, which were stored in an electric field environment, the number of bacteria after storage increased by less than about 10 ³ times compared to immediately after slaughter for the samples from all parts. It was confirmed that it had been suppressed. These results demonstrate the advantages of vacuum shrink wrapping and food storage in an electric field environment.

(Comparative Example 12 and Example 17)
As Comparative Example 12, the proportion of chilled products was calculated when a sample of food package F prepared in the same manner as Comparative Examples 10 and 11 above was stored in a container 10 at a room temperature of -3.2°C for 53 days. It was measured. In addition, as Example 17, when a sample of food package F prepared in the same manner as in Examples 15 and 16 above was stored in a container 10 at a storage room temperature of -3.2°C for 63 days, the results of chilled products were shown. The proportion was measured. These food conditions, storage conditions, and percentage of chilled products are summarized in Table 5. As shown in Table 5, the food package F subjected to vacuum shrink wrapping shown in Example 17 is more suitable for chilled products than the food package F shown in Comparative Example 12 which is not subjected to shrink wrapping. It is understood that the proportion is large, that is, it is difficult to freeze.

(Comparative Example 13 and Examples 18 to 20)
As Comparative Example 13, the change in the number of general viable bacteria was measured when frozen pork belly was thawed in a non-electric field environment. As Example 18, after storing frozen pork belly in a container 10 in an electric field environment of around -3°C for 30 days, it was taken out from the container 10 and stored in a non-electric field environment at 0°C. We measured the changes in As Example 19, the change in the number of general viable bacteria was measured under the same conditions as Example 18, except that the number of storage days in the electric field environment was set to 63 days. As Example 20, the change in the number of viable bacteria was measured under the same conditions as Example 18, except that the number of storage days in the electric field environment was set to 53 days.

In Table 6, the number of days that have passed in Comparative Example 13 indicates the number of days that have passed since the day when the frozen pork belly was thawed. The number of days that have passed in Examples 18 to 20 indicates the number of days that have passed since the day when the frozen pork belly was taken out from the container 10.
As shown in Table 6, in Comparative Example 13, which was not stored in an electric field environment, the number of viable bacteria increased to 7.4 million after about 15 days. On the other hand, in Example 18, which was once stored in an electric field environment, the number of general viable bacteria was 480,000 even after the 20th day, and even after that, the number of general viable bacteria was several hundred thousand until the 50th day. , the increase in the number of viable bacteria is suppressed compared to Comparative Example 13. Similarly, in Examples 19 and 20, when compared with Comparative Example 13, the increase in the number of viable bacteria was suppressed. In this way, it is understood that once stored in an electric field environment, the increase in the number of viable bacteria during thawing can be suppressed.

As mentioned above, the above embodiments, modifications, examples, etc. as examples of the present disclosure have been described in detail, but as described above, the above descriptions merely show examples of the present disclosure in all respects, and the present disclosure It goes without saying that various improvements and modifications can be made without departing from the scope of the invention. Furthermore, the above embodiments can be partially replaced, deleted, or combined.

For example, the step SP4 of forming an electric field inside the storage chamber S10 and the step SP5 of cooling the inside of the storage chamber S10, shown in FIG. 4, may be performed with a time difference.
The total loading amount of food packages F accommodated inside the container 10, the number of food packages F accommodated per one outer container B, the total weight, etc. can be increased or decreased as appropriate.

The process to be applied to the food package F in step SP2 shown in FIG. 4 is not limited to vacuum shrink wrapping, but any process that increases the degree of vacuum inside the food package F can be used. Can be adopted. Note that the process of increasing the degree of vacuum inside the food package F is a process of making the pressure inside the food package F lower than atmospheric pressure. As such a process, for example, a process can be used in which the inside of the food package F is made into a high vacuum without performing shrink wrapping by pulling out air from the inside of the food package F, a so-called deaeration process. can. Even when using a vacuum pack or a deaeration pack that does not involve shrink wrapping, it is possible to obtain functions and effects similar to those of the above embodiment.
Note that non-shrink vacuum packs can be used for semi-dressed marine products such as seafood (for example, salmon) that are currently transported and stored in a naked state without being vacuum packed. Furthermore, for livestock meat such as pork, it is desirable to use vacuum shrink wrapping rather than loose vacuum packaging.

When covering food with a packaging material to produce food packaging F, lactic acid bacteria may be applied to the food. For example, the food package F may be created by packaging a food coated with lactic acid bacteria with a packaging material and then subjecting the packaging material to vacuum shrink wrapping, vacuum packing, or deaeration packing. In addition, when applying lactic acid bacteria to food, it is not necessary to apply vacuum shrink wrapping or non-vacuum shrink wrapping to the packaging material, and simply wrap the food coated with lactic acid bacteria in the packaging material. It may also be used as a package F. In addition, in the flow shown in FIG. 4, the process of step SP4 of forming an electric field inside the storage chamber S10 is deleted, and after storing the food package F in the storage chamber S10 (step SP3), The container 10 may be only cooled (step SP5) and then loaded and transported (step SP6).

DESCRIPTION OF SYMBOLS 10... Container (accommodation), S10... Storage room, 20... Storage main body, 30... Cooling device, 40... Box body, 41... Top wall part, 42, 43... Side wall part, 50... Door part, 60... Electric field Formation part, 61... Insulating member, 62... Electrode member, 81, 82... Placement part, 810, 811, 820, 821... Site, B... Outer container, F... Food package, S10... Storage chamber.

Claims (11)

A food storage method for storing at least one type or form of food, the method comprising:
A storage preparation step of preparing a storage chamber including a storage chamber and an electric field forming section for forming an electric field in the storage chamber;
A food packaging step of forming a food package by covering the food with a packaging material and then performing a process to increase the degree of vacuum inside the packaging material, or preparing the formed food package;
an electric field cooling step of storing the food package in the storage chamber, forming an electric field in the storage chamber, and cooling the inside of the storage chamber to maintain at least a portion of the food in a chilled state;
food storage methods including; In the food packaging step, the food package is formed by covering the food with a packaging material including a heat-shrinkable film and performing vacuum shrink wrapping.
The food storage method according to claim 1. 2. The food storage method according to claim 1, wherein in the food packaging step, as a process for increasing the degree of vacuum inside the packaging material, the interior of the packaging material covering the food is made into a high vacuum. 2. The food storage method according to claim 1, wherein in the food packaging step, a process of increasing the degree of vacuum inside the packaging material includes a process of extracting air from the inside of the packaging material covering the food. When the food package is not housed in the housing chamber or the food package is housed in the housing chamber, an electric field is formed in the housing chamber to cool the housing chamber. Including a temperature measurement process to measure the temperature distribution inside the containment chamber.
The food storage method according to claim 1. In the electric field cooling step, the storage position of the food package in the storage chamber is determined based on the temperature distribution in the storage chamber measured in the temperature measurement step and the type or form of the food.
The food storage method according to claim 5. In the electric field cooling step, the food package is housed in the storage chamber without contacting the cold pack.
The food storage method according to claim 1. carrying out the electric field cooling step for one day or more;
The food storage method according to claim 1. In the electric field cooling step, housing the food package in the storage chamber, forming an electric field in the storage chamber, or cooling the storage chamber starts within 5 days immediately after production of the food.
The food storage method according to claim 1. Transporting the food while performing the electric field cooling step using the food storage method according to any one of claims 1 to 9.
Food transportation methods. A food transporter that contains at least one type or form of food and is transported,
a storage chamber, and a storage chamber including an electric field forming section for forming an electric field in the storage chamber;
A food package formed by covering the food and increasing the degree of vacuum inside;
Equipped with
An electric field is formed in the housing chamber in which the food package is housed, and at least a portion of the food is maintained in a chilled state with the interior of the housing chamber being cooled.
food transporter.

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