JPS6174566A - Preservation of food - Google Patents

Abstract

PURPOSE:To keep the quality of a food for a long period, preventing the quenching of the food by the direct contact with the refrigerant, by putting a volatile refrigerant in a cold-keeping box, and putting the box together with the food to be preserved in a heat-insulating storage box. CONSTITUTION:A sealable heat-insulated box made of foamed synthetic resin is used as a storage and marketing box 1. The food to be preserved, e.g. leaf vegetables such as lettuce, celery, etc. or NATTO (fermented soybeans), etc. is put into the storage box 1. Separately, a heat-insulating cold-keeping box 3 made of the material same as above is prepared, filled with a volatile refrigerant 4 such as dry ice, liquefied nitrogen, etc., sealed, and placed in the above storage box. 1 The outer surface of the cold-keeping box 3 is cooled gradually by the cold atmosphere contacting with the inner wall surface of the cold- keeping box 3, and the space in the storage box 1 is maintained at a temperature lower than the atmospheric temperature.

Description

[Detailed description of the invention] [Industrial application field]

The present invention relates to a method for preserving foods such as leafy vegetables such as celery and lettuce, or natto.

[Conventional technology]

Currently, lettuce, natto, etc. are displayed and sold on shelves in show windows. In the case of these leafy vegetables and natto, in order to maintain the quality at the time of production in stores or on the street and sell them to restaurants and food handlers in factories without reducing the product value, they must be packed in boxes and kept under the required temperature (usually It is desirable to keep the ice cubes at a temperature of around 5℃), and the storage method is as follows: 1. For example, use an insulating container made of synthetic resin foam, as is used for preserving fresh fish, and store ice cubes packed in a film inside. Conventionally, methods of storing food to be preserved together have been considered.

[Problem to be solved by the invention 1] When using film-packed ice cubes, food to be preserved can be rapidly cooled, but the cold retention effect is poor and there is a problem that melted water can penetrate and flow out. . Further, when leaf vegetables are directly exposed to extremely low temperature (-80° C.) air produced by dry ice or the like, a so-called frost blight phenomenon occurs, resulting in discoloration and a decrease in commercial value, as well as a change in taste. On the other hand, natto has the problem of freezing and hardening due to the cold air of dry ice, making it almost impossible to eat, and there is a need for an easy preservation method at the final distribution stage (hot sale stage). [Means for Solving the Problems] In view of the above-mentioned points, the present invention is intended to provide a method for preserving foods suitable for selling over-the-counter or on the street at the final distribution stage. It is designed to prevent food from deteriorating, and at the same time further improve the sustainability of the cold preservation effect, so that the quality of foods that are easily deteriorated by cold air at the time of retail sale can be maintained at the same level as when they were produced. However. The object of the present invention is to use a sealable heat insulating storage box made of synthetic resin foam, and a sealable cold storage box that can be stored in the storage box and made of the same material as the storage box. A volatile refrigerant such as dry ice or liquid nitrogen is stored in the storage box and the storage box is sealed, and the storage box is placed in the storage box together with the food to be preserved, and the inside of the storage box is kept under a cool atmosphere by the volatile refrigerant. This is achieved by a food preservation method that allows storage. [Example] The present invention will be explained below with reference to the attached drawings.
A sealable insulating container made of a synthetic resin foam such as expanded polystyrene, expanded polypropylene, expanded polyethylene, etc. with a density of 15 g/Q to 100 g/n is used as the storage box 1 that also serves as food sales. The food to be preserved 2 such as leafy vegetables such as lettuce and celery, or natto is stored therein. On the other hand, a cold insulating box 3 made of the same material as the storage box 1 and having heat insulating properties is prepared, and a volatile refrigerant material 4 such as dry ice or liquid nitrogen is filled in the cold insulating box 3. The present invention is carried out by sealing the box 3 and storing it in the storage box 1. The storage box 1 and the cold storage box 3 are each equipped with lids 1a and 3a that can be sealed tightly, and the storage box 1 is equipped with a hanging string 5 for carrying. It is practically preferable that the volume ratio of the box 3 is 5 to 20:1. Effects of the Invention The present invention is as described above, and the cold air generated by the volatile refrigerant cools the inside of the cold storage box, and the cold air acting on the wall surface of the cold storage box gradually cools the surface side of the cold storage box. As a result, the inside of the storage box can be placed in an atmosphere with a lower temperature than the outside air. therefore. Unlike the conventional cold storage method using ice cubes in film packs, the food to be preserved stored in the storage box is cooled indirectly by volatile refrigerants such as dry ice and liquid nitrogen inside the storage box. Because the product is placed in an atmosphere of In addition, since the volatile refrigerant material is housed in an insulated cold box, its lifespan can be extended and the sustainability of the cold storage effect has been significantly improved, increasing the commercial value of foods at retail over a long period of time. Moreover, there is no need to worry about the product deteriorating due to damage caused by the product, and if the customer wishes, the product can be sold with a storage box so that the customer can take it home as it is, which is a sales advantage. A useful food preservation method can be provided.

[Brief explanation of drawings]

The drawing is a partially cutaway perspective view of an article in which the method of the present invention was applied. In the figure, 1 is a storage box, 1a is a lid, 2 is food to be preserved, 3 is a cold box, 3a is a lid, and 4 is a volatile refrigerant material.

Claims (1)

[Claims] A sealable insulating storage box made of synthetic resin foam and a sealable cold storage box made of the same material as the storage box are used. A volatile refrigerant material such as nitrogen is contained and sealed, the cold storage box is housed in the storage box together with the food to be preserved, and the inside of the storage box is placed under a cool atmosphere by the volatile refrigerant material. How to preserve food.