JPH04121177A - Keeping freshness of food and the like - Google Patents

Abstract

PURPOSE:To enable transportation for a long distance and a long time by enabling storing for a long period of time by receiving food, etc., in a heat insulation vessel made of a foamed synthetic resin, subjecting to pre-cooling under vacuum in a state of closed cover and charging a gas for freshness keeping in the vessel. CONSTITUTION:Vegetables, fruits, fishes, meats and other foods, etc., are received in a heat insulation vessel composed of a main body 1 and a cover 2 of the vessel made of a foamed synthetic resin and the vessel is received in a vacuum chamber, then pressure in the vacuum chamber is reduced by compulsorily discharging air in the vessel through a communicating part 6 for ventilation provided in a suitable position in the vessel, thus the received materials are pre-cooled. Next, pressure in the vacuum chamber is recovered with a gas for keeping freshness of the received materials as the gas of pressure recovering and said gas is charged in the vessel, then held in an enclosed state, thus the chamber is treated for transporting and storing, etc., to keep freshness of the food, etc.

Description

[Detailed Description of the Invention] [Industrial Field of Application] The present invention provides a cooling container made of foamed synthetic resin that stores vegetables,
Fruits, fish, meat, and other foods can be stored in the container and pre-cooled under vacuum with the lid closed. After pre-cooling, the inside of the container is filled with freshness-preserving gas to keep the food inside the container cool, such as vegetables and fruits. In some cases, their physiological metabolism releases ethylene gas, accelerating their own wear and tear, or the pre-cooling effect is prematurely lost due to internal temperature rise due to respiration, and in the case of fish and meat, discoloration. This invention relates to a method for preserving the freshness of foods, etc., so as not to damage the product value.

[Conventional technology]

BACKGROUND ART Conventionally, when vegetables, fruits, fish, meat, and other foods are shipped from a shipping source, they are sometimes shipped after being pre-cooled. These foods, etc. are usually precooled by forced precooling, differential pressure precooling, or vacuum precooling using equipment provided at the shipping source, or by appropriately selecting a precooling method suitable for the food. In particular, vegetables tend to shed some of their retained moisture, and in recent years, it has become increasingly common for vegetables to be precooled by vacuum precooling, which can be completed in a short time.

In the case of 2, as shown in FIG. 15, a cooling container consisting of a container body A made of foamed synthetic resin and a lid body B also made of foamed synthetic resin, which is fitted onto the container body A in an airtight manner, is placed in the appropriate place.
For example, as shown in the figure, a cover body B is provided with a through hole C for ventilation having a diameter of about 10 mm. Then, the vegetables are stored in the container body A of such a cold storage container, the lid is closed, and the container is placed in a vacuum chamber as it is, and the pressure inside this vacuum chamber is reduced to, for example, about 5 mmHg. The air inside the container is forcibly evacuated through the container to evaporate some of the moisture held in the contents.
By removing latent heat of vaporization, the contents in this container are precooled. Next, by restoring the pressure inside the vacuum chamber, the inside of the container is also returned to atmospheric pressure, and after this, the through hole C is sealed with adhesive tape, etc., and handling such as transportation and storage is performed.

[Problem to be solved by the invention]

However, when doing this, not only does it take more time to seal the through-hole compared to the pre-cooling operation that takes about 20 to 30 minutes to separate the diameter, but it also takes a lot of time to seal the through holes. In the same way, ethylene gas released by physiological metabolism accelerates its own wear and tear, and the internal parts of vegetables and fruits, as well, gradually rise in temperature due to respiration and over time. Over time, the pre-cooled state is lost, and the internal temperature rises, which further increases the respiratory action, resulting in a sudden drop in the freshness of vegetables or fruits.

Furthermore, if the stored material is fish or meat, there is a risk that the product's value may be lost due to discoloration.

In view of these conventional problems, the present inventor has made it possible to perform the vacuum pre-cooling operation without any hassle, and further maintains the freshness of food etc. after vacuum pre-cooling for an even longer period of time. Increased reliability and thereby long distances,
The present invention was developed with the aim of research that would enable long-term transportation and long-term storage.

[Means to solve the problem]

In order to perform the vacuum precooling operation without any trouble and to maintain the freshness of the food after vacuum precooling for a longer period of time, claim 1 of the present invention provides a container body made of foamed synthetic resin. Vegetables, fruits, fish, meat, and other foods are stored in a cold container with a lid, and then stored in a vacuum chamber, and by reducing the pressure in the vacuum chamber, The air inside the container is forcibly evacuated through the ventilation communication section, which pre-cools the contents, and then when the inside of the vacuum chamber is restored to pressure, the gas for keeping the contents fresh is used as the pressure recovery gas, and then the container is This gas is filled into the container and held in a substantially sealed state,
The gist of this book is how to preserve the freshness of foods, which are characterized by handling such as transportation and storage. In addition, claim 2 provides a cold storage container in which one of the fitting means is provided at one of the joints between the container body and the lid, and the other fitting means is provided at the other joint, and the lid of the container is closed. In some cases, a required length is provided on the joining surface side of one and/or the other of the fitting means in the longitudinal direction of the fitting means so that a ventilation passage communicating with the inside and outside is formed between one and the other of the fitting means. An example is provided in which a long groove is provided, and one end of the groove is provided with an inner surface opening facing into the container, and the other end thereof is provided with an outer surface opening facing outside the container.
Therefore, in claim 2, the cross-sectional area and/or length of the concave groove of the cold storage container is set such that when there is no pressure difference between the inside and outside of the container, free air or other gas can flow due to viscous resistance and film frictional resistance. An example is shown in which the flow is substantially blocked. Further, in claim 4, the gas pressure for pressure recovery is set to be higher than atmospheric pressure, and in claim 5, a low temperature gas is used as the freshness-keeping gas. Moreover, in claim 6, it is exemplified that a gas suitable for suppressing the physiological metabolism, respiratory action, or oxidation action of the stored material is used as the freshness-keeping gas.

[For production]

Then, vegetables, fruits, fish, meat, and other foods are placed inside the container body of a cooling container made of foamed synthetic resin, and the lid is closed, and the container is placed in a vacuum chamber. By reducing the pressure inside the vacuum chamber, the air inside the container is forcibly exhausted to the outside through the ventilation passage, which evaporates some of the moisture held in the contents and pre-cools it by taking away the latent heat of vaporization. . When restoring the pressure inside the vacuum chamber after the pre-cooling operation, this repressurizing gas is used to suppress the physiological metabolism and respiratory effects of vegetables and fruits, and to prevent discoloration of fish and meat. In order to prevent this, we use gas to keep the contents fresh.
Subsequently, this gas is filled into the container and held in a substantially sealed state. Food products are transported, stored, and handled while the freshness-preserving gas is kept in the container.

〔Example〕

The details of the method for preserving the freshness of foods, etc. according to the present invention will be further explained based on the cold storage container used therein. FIGS. 1 and 2 show an example of such a cold storage container. 1 in the diagram
2 is a box-like container body made of foamed synthetic resin with an open upper surface, and 2 is a lid body also made of foamed synthetic resin that closes the upper opening of the container body 1 in an airtight state. This cold storage container is provided with a fitting means at the joint between the lid 2 and the container body 1 so that the lid 2 can be hermetically closed to the container body 1. In the illustrated container, a protrusion 4 is provided along the inner surface of the upper surface of the side wall 3 of the container main body l, and
On the outer periphery of the lower surface of the lid body 2, a concave strip 5 which is fitted into the protruding strip 4 is provided along the entire outer periphery of the lower surface. When the container is closed, the concave line 5 on the lid body 2 side is fitted into the convex line 4 on the container body 1 side.
A groove 7 is formed from the outer surface of the groove 5 to the bottom surface with the diagonal corner of the lid body 2 in between, so that a ventilation communication part 6 that communicates with the inside and outside is formed between the groove 5 and the groove 5. Furthermore, a fan-shaped recess is formed on the inner surface of the groove 5 at one end of the groove 7 located on the inner surface side of the groove 5, and an inner surface opening 8 and a recess are formed on the inner surface of the groove 5. At the other ends of the strips 5 located on the outer surface side, fan-shaped recesses are formed on the outer peripheral lower surface of the lid body 2, and outer surface side openings 9 facing outside the container are provided. The cross-sectional area and/or length of this groove 7 is such that when the container is closed and there is no pressure difference between the inside and outside of the container, free flow of air or other gas is prevented due to viscous resistance and membrane friction resistance. It is formed to such an extent that it is substantially blocked. Here, the film frictional resistance is based on the film theory that states that a thin layer of air or other gas attached to a certain surface cannot be removed even if the surrounding area is in a complete vacuum. It is the resistance that occurs between an adherent layer of air or other gas and the air or other gas that attempts to flow outside of it.

Next, FIGS. 3 and 4 show modified examples of the cold storage containers shown in FIGS. 1 and 2, respectively. In the cold storage container shown in FIG. 3, a groove 7 is provided from the upper surface to the outer surface between the corners of the protruding strip 4 provided on the side of the container body 1, and the upper surface of the protruding strip 4 is connected to the groove 7. Similarly to the container shown in FIGS. 1 and 2, an inner opening 8 and an outer opening 9 are formed on the upper surface of the side wall 3 outside the ridge 4 in a fan-shaped recess, so that when the container is closed, , a ventilation communication section 6 is provided to communicate the inside and outside of the container. In addition, the cold storage container shown in FIG. 4 is provided with a groove 7 in the length direction of the protrusion 4 on the upper surface of the side wall 3 of the container body l from the upper surface of the protrusion 4 to the outer surface, and is communicated with the groove 7. An inner opening 8 on the upper surface of the protruding strip 4 and an outer opening 9 on the upper surface of the side wall 3 outside the protruding strip 4 are formed in a fan-shaped recess similarly to the container shown in FIGS. 1 and 2. A ventilation communication section 6 is provided.

In these cold storage containers, grooves 7 are provided in the longitudinal direction of the fitting means on the joint surface side of the fitting means at appropriate positions provided at the joint between the container body l and the lid body 2, and the grooves 7 are formed in the longitudinal direction of the fitting means. An inner side opening 8 facing into the container from one end and an outer side opening 9 facing outside the container from the other end are formed to provide a ventilation communication part 6 that communicates between the inside and outside when the container is closed. be. For this reason, vegetables and the like are stored in the container body 1, closed with the lid 2, and then placed in a vacuum chamber in a plurality of containers, connected and stacked so that at least the outer opening 9 is not blocked. When the pressure inside this vacuum chamber is reduced to, for example, about 5 mmHg, the air inside the container is forcibly exhausted from the inner surface side opening 8 through the groove 7 to the outside of the container from the outer surface side opening 9, and the air contained in the container is Evaporates some of the moisture held in the contained material,
By removing the latent heat of vaporization, it is possible to pre-cool the temperature to approximately 2 to 5°C. After the pre-cooling operation, in the present invention:
When repressurizing the inside of the vacuum chamber, a freshness-preserving gas is used to suppress the physiological metabolism and respiratory effects of the vegetables, etc. stored inside the container, and this gas is then applied to the outside surface. The container is filled from the side opening 9 through the groove 7 and from the inner side opening 8. After the pressure inside and outside the container becomes almost the same, the container is filled with freshness-preserving gas, and the gas inside the container is cooled and becomes more dense, making it difficult to flow. The viscous resistance that occurs when other gases flow through this groove 7 and the groove 7
The flow of outside air into the container is substantially blocked by the film frictional resistance created between a layer of air or other gas that is thinly adhered to the wall of the container and does not flow. For this reason, the freshness-preserving gas is substantially kept sealed inside the container. In this way, once the freshness-keeping gas is sealed in the container, in order to make it more difficult for the freshness-keeping gas inside the container to be replaced by the air outside, the gas pressure of the freshness-keeping gas for repressurization should be adjusted. It may also be considered as appropriate to raise the pressure to above atmospheric pressure, for example by setting it to 1.1 atm, or to use low-temperature gas as a freshness-preserving gas and allow it to thermally expand within the container after filling. .

This freshness-maintaining gas is a gas suitable for suppressing the physiological metabolism, respiration, or oxidation of the stored contents, and is used when the purpose is to suppress the physiological metabolism of vegetables and fruits. For example, a gas with a high concentration of carbon dioxide is effective; for example, a gas with 70% nitrogen, 25-20% oxygen, 5-10% carbon dioxide, or 30% nitrogen and 30% oxygen.
, a gas with 40% carbon dioxide, and 60-80% nitrogen,
A gas containing 40 to 20% carbon dioxide can be used.

Gas with such a high concentration of carbon dioxide also suppresses the generation of microorganisms, and is considered to be effective in preventing the contents from rotting. In addition, when suppressing the respiratory effects of vegetables and fruits, a gas having an oxygen concentration lower than that of the air or a gas containing no oxygen at all is used. When such a gas is used, it is also effective in preventing the oxidation of the oil when the food in the container contains a lot of oil.

In the case of fish and meat, in order to prevent their discoloration, for example, 70 to 80% oxygen and 30 to 20% carbon dioxide.
It was preferable to use a gas of

Regardless of the illustrated cold storage container, the convex strips 4 and concave strips 5, which serve as one and the other of the fitting means, are not provided around the entire outer circumference of the container, but are provided only at the four corners with corner portions in between, or It can also be provided on a pair of facing sides. Also, as for the shape of the inner surface side opening 8 and the outer surface side opening 9, various shapes other than the fan-shaped recesses as shown are possible.
If the cross-sectional shape is shaped so that viscous resistance and film frictional resistance are effectively exerted, for example, in the shape of a slit, it will be easier to remove air when forcibly exhausting the air inside the container, and the pressure inside and outside the container will be reduced. It is preferred that the flow of air or other gases be substantially blocked when the difference no longer exists. Furthermore, it is also possible to provide the groove 7 across both one and the other of the fitting means, that is, both the protrusion 4 and the groove 5.

If the cross-sectional area and/or length of the concave groove 7 provided between the container body l and the lid body 2 is large enough that there is no pressure difference between the inside and outside of the container, air can flow freely due to viscous resistance and membrane friction resistance. As a result of various experiments, the cold storage container formed to such an extent that it is substantially blocked is, for example, as shown below.

As shown in Figure 5 (A), the width a of the groove 7 is 5 mm, the height is 4 ml1, and the length b from the bent part to the end of the groove 7 is 30 mm.
mm, and the width C of the inner side opening 8 and the outer side opening 9 is 2.
0 and the height to 2 mm, the length is 440 mm, the width is 320 mm, and the height is 185 m, as shown in Figure 5 (b).
A refrigerated container is shown in FIG. 6 (a), in which four ventilating holes 6 are provided between the corners of the container body 1 side or the lid body 2 side of a container made of expanded polystyrene molded into a shape of m. As shown, the width d of the groove 7 is 5mm, the height is 3mm, the length e is 60mm, the width f of the inner side opening 8 and the outer side opening 9 is 20mm, and the height is 2mm. , length 440 as shown in Figure 6 (b)
An example is a cold storage container, etc., in which four ventilation recesses 6 are provided at positions other than the corners of the container body 1 side or the lid body 2 side of a container made of expanded polystyrene molded to have a width of 320 mm, a width of 320 mm, and a height of 185 mm. I can show it. Here, in order to increase the viscous resistance and film frictional resistance, see Figure 5 (a) and (b).
As shown in FIG. 2, bending the groove 7, reducing the cross-sectional area due to the width and depth of the groove 7, or increasing the length may be appropriately considered. The effect can be effectively achieved by increasing the number of grooves 7 provided, decreasing the cross-sectional area, or increasing the length. The number of grooves, as well as the cross-sectional area and length of the grooves can be set appropriately.

Next, FIGS. 7, 8, and 9 show other embodiments of the cold storage container. In this cold storage container, the side wall 3 of the container body 1
Along the inner surface of the top surface, a protruding strip 4 is provided along the entire circumference of the side wall 3, and on the outer periphery of the lower surface of the lid body 2, a concave strip 5 that fits into the protruding strip 4 is similarly provided on the entire outer periphery of the lower surface. It is set up.

When the container is closed, the concave line 5 on the lid body 2 side is fitted into the convex line 4 on the container body 1 side, but at this time there is a groove between the convex line 4 and the concave line 5. The size relationship and/or positional relationship between the protrusions 4 and the grooves 5 is determined so that a gap lO as shown in FIG. 9 is formed on the upper surface side of the protrusions 4 and on the outer surface side of the protrusions 4. In the figure, reference numeral 11 denotes an interior convex portion that is installed in the upper part of the opening of the container body 1 along the inner surface of the side wall 3 of the container body 1 which is located on the lower surface of the lid body 2. By providing this interior convex portion 11, when the container is closed, a gap 10 is formed around the entire outer circumference of the container. Next, reference numerals 8.9 and 8.9 are connected to the gaps 10, sandwiching the diagonal corners of the container between them, and displacing the positions to form fan-shaped recesses. Similar to the cold storage container shown in FIG. 4, it has an inner surface opening facing into the container and an outer surface opening facing outside the container. Here, the cross-sectional area of this gap 10 and/or the length of the gap 10 between the inner surface side opening 8 and the outer surface side opening 9 are determined by the viscous resistance and convexity generated between air and other gases trying to pass through. Film friction that occurs between a layer of air or other gas that is thinly adhered to the upper and outer surfaces of the strip 4 and the bottom and inner surface of the grooved strip 5 and does not flow, and the air or other gas that passes through this layer. Due to the resistance, the inner opening 8
The opening 9 is formed to such an extent that the flow of air or other gas is substantially blocked when there is no pressure difference between the opening 9 and the opening 9 on the outer surface side. Then, vegetables, fruits, fish, etc. are placed inside the container body 1.
When meat or other foods are stored and the lid 2 is closed, a gap 10 is formed around the entire outer periphery of the container between the protruding strip 4 on the container body 1 side and the grooved strip 5 on the lid 2 side, Moreover, as shown in FIGS. 7, 8, and 9, the inner surface opening 8 and the outer surface opening 9, which are spaced apart and displaced in position, are connected to this gap 1.
Connects to 0. That is, in this cold storage container, a ventilation passage 6 is formed from the gap 10, the inner opening 8, and the outer opening 9. An example of such a cold storage container is, for example, as shown in Figure 1O (a), (b), and (c), it is made of polystyrene foam molded 55 times larger and has a wall thickness of 22 mm, and the inner dimensions are 405 mm in length and 295 mm in width. , height 135 m
The width g of the protruding strip 4 provided on the side of the container body 1 is 10 mm on a container that can be closed in an airtight state consisting of a container body l and a lid body 2.
There is a gap 10 of 2 mm between the upper surface side and the outer surface side of this protrusion 4.
In addition, the width of the inner opening 8 is set to 30 mm, the height i is set to 2 mm, and the width of the outer opening 9 is set to j.
20 mm, and the height k is 2 mm, respectively, and are formed in the positional relationship as shown in (a) and provided with the ventilation communication portion 6.

Next, FIG. 11 and FIG. 12 each show still other embodiments of the cold storage container. The cold storage container shown in FIG. 11 has a ventilation communication section 6 that communicates between the inside and outside of the container, which is made of a foamed synthetic resin container body 1 and a lid 2, in a stepped part of the bottom wall 12 on the outer periphery of the container body 1. A pipe material 15 of a required length is attached with one end to the mounting port 14 and directed into the container from the mounting port 14 that is drilled into the container from the outside of the pipe 13. It was erected. This pipe material 15 has, for example, an outer diameter of 6 mm, an inner diameter of 5 mm, and a length of 1 mm.
20 mm etc. are available. Moreover, the cold storage container shown in FIG. 12 includes a container body 1 and a lid body 2 made of foamed synthetic resin.
An opening 1 of a required length that communicates with the inside and outside at a suitable location of a container made of
6 is bored to provide a ventilation communication section 6. Then, the cross-sectional area on the inner surface side of these pipe materials 15 and/or
or the length and/or the cross-sectional area and/or length of the opening 16 such that free flow of air or other gas is substantially blocked due to viscous drag and film frictional drag in the absence of a pressure difference inside and outside the container. It is formed to a certain degree.

Furthermore, as a cold storage container, Figure 13 (a), (b), and (c)
As shown in FIG. 14(A), a slit 17 is formed in the upper part of the side wall 3 of the container body 1 so that the bottom surface is flush with the bottom surface, the bottom surface is made to protrude from the center, or is recessed in the thickness direction of the side wall 3.
As shown in (b), there is a diagonal transverse shape in plan view, and as shown in (b), there is a bent shape in plan view with bent parts provided at the center of the side wall 3 in the longitudinal direction from the ends toward the inner and outer sides of the container. , as shown in (c), it is also possible to use a bellows transverse shape in plan view, and as shown in (d), in plan view, it is partially joined in a partially overlapped shape in plan view. The cross-sectional area and/or length of the slit 17 is also determined to such an extent that viscous resistance and membrane frictional resistance are effectively exhibited.

In addition, the present applicant has applied a cold storage container with an opening having an orifice effect, which was previously filed as Utility Model Application No. 1989-89589, and a film-like check valve, which was filed as Utility Model Application No. 63-171292, with an opening. It is also possible to use such an opening as the ventilation communication section 6 by using a cold storage container provided in the cooling container.

Furthermore, in order to provide the ventilation communication section 6 in the cold storage container, it is necessary to provide the groove 7, the gap 10, the pipe material 15 or the opening 16, and the slit 17, or to provide an opening with an orifice effect or a film-like check valve. Two or more openings may be provided in combination as appropriate.

When a container made of foamed synthetic resin is used as the container used in the present invention, light can pass through the inside, allowing food such as vegetables, vegetables, etc.
In the case of fruits, the problem is that photosynthesis causes wear and tear. For this reason, it is considered appropriate to provide an aluminum vapor-deposited layer or other light transmission blocking layer on the inner and/or outer surface of the container to block light transmission, or to use colored beads for the foam beads that make up the container. Ru. Experiments have shown that when colored beads are used as the foam beads that make up the container, their light transmission blocking performance is better in the order of white, gray, and black, and that it is better in the order of yellow, green, and blue. .

In addition, containers made of foamed synthetic resin may have problems with the permeation of certain gases, and may require a layer on the inner and/or outer surfaces of the container to block gas permeation, such as the aluminum vapor-deposited layer described above. It is also possible to consider providing the layer in combination with a light transmission blocking layer, or by attaching a synthetic resin film or sheet.

〔Effect of the invention〕

In the method for preserving the freshness of foods, etc. according to the present invention as described above, vegetables, fruits, fish, meat, and other foods are stored inside a cooling container made of foamed synthetic resin, and the lid is closed. The container is pre-cooled in vacuum through the ventilation passage, and after pre-cooling, the container is filled with a freshness-preserving gas to maintain the gas in a substantially sealed state. If the pre-cooling effect is lost due to time-consuming work or sealing of the opening, or if the food inside is vegetables or fruits, their physiological metabolism will release ethylene gas and cause wear and tear on the food itself. or the precooling state is impaired due to internal temperature rise due to respiration,
Furthermore, in the case of fish and meat, when the temperature is 4°, there is less chance of fading and loss of commercial value. As a result, the reliability after pre-cooling is increased, which enables long-distance and long-term transportation and long-term storage.

[BRIEF DESCRIPTION OF THE DRAWINGS] Fig. 1 is a perspective view showing an example of a cold storage container used in the method for preserving the freshness of foods, etc. according to the present invention, Fig. 2 is a perspective view showing a part of the same, and Fig. 3 is a perspective view showing a part of a modified example of the cold insulating container shown in FIGS. 1 and 2, and FIG. 4 is a perspective view showing a part of another modified example of the cold insulating container shown in FIGS. 1 and 2. Figures 5 (a), (b), and 6 (a) and (b) are explanatory diagrams showing the size and positional relationships of the main parts of the cold storage container, respectively, and Figure 7 is another aspect of the cold storage container. FIG. 8 is a perspective view showing a part of the same, FIG. 9 is a vertical cross-sectional view showing the main part, and FIGS. An explanatory diagram showing the size relationship and positional relationship of the main parts,
FIGS. 11 and 12 are longitudinal sectional views showing the main parts of still other embodiments of the cold storage container, and FIGS. Longitudinal sectional view shown, 1st
Figures 4 (a), (b), (c), and (d) are cross-sectional views, No. 15.
The figure is a perspective view showing a conventional cold storage container. DESCRIPTION OF SYMBOLS 1: Container main body, 2: Lid body, 3, Side wall, 4 Convex line, 5: Concave line, 61 Ventilation communication part, 7: Concave groove,
8: Inner side opening, 9: Outer side opening, l
O: Gap, 11: Interior convex portion, 12: Bottom wall, 13: Stepped portion, 14: Mounting port, 15: Pipe material 16. Opening, 17: Slit. Patent applicant: Kanebuchi Chemical Industry Co., Ltd. Figure (b) (d) Figure (a) (c) (a)

Claims (1)

[Scope of Claims] 1) Vegetables, fruits, fish, meat, and other foods are stored in a cold storage container made of a foamed synthetic resin container body and a lid, and then stored in a vacuum chamber. By reducing the pressure inside this vacuum chamber, the air inside the container is forcibly evacuated through a ventilation passage provided at an appropriate location in the container to pre-cool the contents, and then when the inside of the vacuum chamber is restored to pressure, this regeneration is performed. Freshness of foods, etc. characterized by using a gas for keeping the contents fresh as a pressurized gas, and then filling a container with this gas and keeping it in a substantially sealed state for transportation, storage, etc. Retention method. 2) As a cold storage container, one of the fitting means is provided at one of the joints between the container body and the lid, and the other fitting means is provided at the other joint, and when the container is closed, one of the fitting means is provided. A concave groove of a required length in the longitudinal direction of the fitting means is formed on the joint surface side of one and/or the other of the fitting means so that a ventilation communication portion communicating with the inside and outside is formed between the fitting means and the other. 2. The method of preserving the freshness of foods, etc. according to claim 1, wherein said groove is further provided with an inner opening facing into the container at one end and an outer opening facing outside the container at the other end. 3) The cross-sectional area and/or length of the concave groove of the cold storage container can be adjusted to substantially block the flow of free air or other gases due to viscous resistance and film friction resistance when there is no pressure difference between the inside and outside of the container. 3. The method for preserving the freshness of foods, etc. according to claim 2, wherein the food is formed to such an extent that 4) The method for preserving the freshness of foods, etc. according to claims 1 to 3, wherein the pressure of the gas for pressure recovery is higher than atmospheric pressure. 5) The method for preserving the freshness of foods, etc. according to claims 1 to 4, wherein a low temperature gas is used as the freshness preserving gas. 6) The method for preserving the freshness of foods, etc. according to claims 1 to 5, wherein a gas suitable for suppressing the physiological metabolism, respiratory action, or oxidation action of the stored material is used as the freshness-maintaining gas.