JPS58116666A - Preparation of packaged food - Google Patents

Abstract

PURPOSE:To prepare a packaged food having improved keeping quality for a long term, by packaging a food in a specific porous base material, and sterilizing the packaged food under heating by the dry heat. CONSTITUTION:A perishable food, unprocessed food or semiprocessed food, etc. is packaged in a porous material, e.g. a polyester nonwoven fabric having 10-150g/m<2> basic weight, having 1-250sec time required for 100cc air to permeate therethrough per 1 square inch area at ordinary temperature and pressure, and the opening part is tightly heat-sealed and then sterilized at 80-250 deg.C by the dry heat. Thus, the spoilage by microorganisms can be suppressed as much as possible during the storage for a long term, and the life can be prolonged.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing packaged foods, in particular fresh foods,
The present invention relates to a method for preventing microbial contamination during long-term storage of unprocessed foods, semi-processed foods, etc. by packaging unprocessed foods, semi-processed foods, etc. with a specific porous substrate and then subjecting them to dry heat treatment.

It is known that medical instruments such as scalpels, tweezers, and syringes are hermetically packaged with porous substrates and sterilized using steam or hot water at 100° C. or higher.

This kind of porous base material can be sealed and packaged individually.
In addition to high-temperature steam above 00℃, water vapor and water (c)
A material having numerous a-pores that allow microorganisms to pass through is used. The size of the pores must be about 0.577711φ or less, which is smaller than the size of bacteria, and preferably 0.1 μmφ or less, which is smaller than the size of viruses. For example, open cell microporous films made of polyester, polyimide, polypropylene, etc. Although it has been put into practical use, it is extremely difficult to produce an IJB using a film in which countless micropores are uniformly opened, and it must be quite expensive.

On the other hand, films made of polyethylene, polypropylene, polyester, etc. are used for food packaging as mentioned above, but most of these are non-porous films manufactured by normal methods and do not have breathability. If the contents are heated and sterilized after being sealed, the air inside will expand and the seal will peel off, making it impossible to effectively prevent microbial recontamination after sterilization. For this reason, vacuum packaging technology has also been developed, but the equipment required for vacuum packaging is quite heavy, and it lacks versatility for simple packaging.

The present inventor focused on the above circumstances and developed packaging and packaging for medical devices.
By applying sterilization technology to simple food packaging, it is possible to easily package and sterilize food, and after sterilization, it is possible to prevent the invasion of microorganisms as much as possible and extend the shelf life. We have been conducting research to establish a new technology. The present invention relates to such research.

It was completely defeated as a result, and the composition was that food was packaged with a multi-purpose material that required 1 to 250 seconds for 100 cr of air to pass through per square inch of area at room temperature and normal pressure. The gist is that after that, dry heat sterilization treatment is performed at 80 to 250°C.

As mentioned above, the packaging base material used in the present invention must be such that the number of seconds required for the passage of 100 CI-9 air per square inch of area at room temperature and normal pressure is in the range of 1 to 250 seconds. If the heating time exceeds 250 seconds, the water vapor generated from the contents during heat treatment cannot escape to the outside, and the seal portion will expand and peel, making it impossible to prevent microbial contamination.

On the other hand, if the time required for passage is less than 1 second, although sterilization by heat treatment can be performed efficiently, the pore size is too large and it is not possible to effectively prevent the invasion of microorganisms during storage. Purpose of prevention'fK: cannot be led astray. However, if the number of seconds ν required for air to pass is within the above-mentioned preferred range, the water vapor generated from the internal medicine during dry heat treatment will easily escape to the outside through the pores, so that the seal portion will be There is no fear of persimmons peeling off, and even if left after sterilization, the invasion of microorganisms can be effectively prevented.

As a result, it depends on the type of contents, moisture content, etc.

Depending on the 8If class, it is possible to prevent spoilage due to microorganisms for up to 6 months or even longer. In addition, many foods, especially foods with high moisture content, change their taste due to internal deterioration and decrease their commercial value after 6 months, even if they do not undergo deterioration due to the proliferation of microorganisms.
The lifespan of general packaged foods is said to be limited to about 6 months, and σJ1 says that about 6 months is sufficient to prevent deterioration due to microorganisms.

Foods that are sterilized and packaged according to the present invention (~deni, wildflowers, fruits,
Natural foods such as meat, fish and shellfish, eggs, grains, and beans, noodles, Japanese and Western sweets, bread, cakes, castella, ham and sausages, dairy products, chikuwa, kamohako, tobu, fried tofu, and salads. , Dough before cooking of processed foods such as delicatessen, cooked rice, mochi, gyoza, onigiri, etc., or semi-cooked products,
Examples of songs include songs that have finished heating tone 'f3J,
Among these, foods with high moisture content are suitable for packaging according to the present invention.

Cooked foods with a high moisture content will spoil in 1 to 3 days if left alone, but by adopting the above sterilization packaging method, the period until spoilage can be extended by more than 1.5 times. This is extremely effective for converting new retort food products, prepared foods, etc.

In addition, the porous substrate used in the present invention includes a film,
Paper, non-woven fabric, etc. are available, and porous films are made by blending a paste resin such as nylon, polyester, polyimide, polypropylene, polyolefin, etc. with other insoluble resins or inorganic powder, extruding the mixture, and stretching the mixture. Examples include those in which countless micropores are formed by film stretching, or those in which porosity is imparted by changing the stretching conditions of the film (Japanese Patent Publication No. 46-40119, etc.). It may be selected appropriately according to A[.

Paper can be made not only from ordinary vegetable cellulose, but also from synthetic paper made from synthetic fibers such as polypropylene, polyolefin, nylon, polyester, polyimide, etc., as well as synthetic paper made from synthetic fibers such as polypropylene, polyolefin, nylon, polyester, and polyimide. The number of seconds required for aeration can be adjusted by changing the beating circumference of the cellulose raw material, the diameter of the kat, paper-making conditions, basis weight, etc.

In addition, nonwoven fabrics are almost the same as the synthetic paper, and include polypropylene, polyolefin, nylon, polyester,
Those manufactured from short or long fibers such as polyimide are used. In the case of a nonwoven fabric made of 5Jll of thermoplastic 1, it has heat-sealing properties by itself, so it can be sealed without using an adhesive, so it can be used in applications where adhesives are not desired. .

Among the above porous substrates, this is a nonwoven fabric obtained from a particularly preferred polyester fiber. However, general polyester fibers have a melting point of around 260°C and have excellent heat resistance, and the nonwoven fabric obtained therefrom can sufficiently withstand dry heat treatment at about 250°C. Moreover, if dry heat treatment is carried out at temperatures above 250℃, ordinary foods will become burnt and the taste will be significantly impaired, so it is almost impossible to process them at higher temperatures than this. If it has heat resistance, it can be used for sterile packaging of most foods.

Furthermore, although the size of the opening in paper and nonwoven fabric is larger than the size of the microorganism, since the fibers are stacked on top of each other, each hole has a winding structure, allowing steam and water to pass through. Microorganisms are trapped in the middle of the superimposed structure of fibers and are difficult to pass through. If food is hermetically packaged using paper or non-woven fabric with such a structure and heated with steam or hot water of 100°C or higher, the steam or hot water will pass through the through holes and reach the food packaged inside, sterilizing it. can be done. Furthermore, even if the food is left outside after sterilization, even if microorganisms enter through the openings, they will be caught in the middle of the stacked structure of fibers, so re-contamination of the food inside is unlikely. A polyester non-woven fabric (with a size of 10 to 150 Fi/m) using Shojisen fibers or long #i# fibers can be easily obtained, and the polyester non-woven fabric can be layered for the number of seconds required for the passage. Alternatively, the size can be adjusted as desired by partially blocking or reducing the size of the first hole with a heating roller or the like.

The heat resistance of porous substrates other than polyester is 1, for example, nylon is around 200°C, polypropylene is around 150°C, and general paper is around 140°C.

A method of packaging food with the porous base material; [7] A method of placing food in a bag or tray made of the porous base material and heat-sealing the opening using heat, high frequency, ultrasonic waves, etc. When using a porous base material with poor heat-sealability, it is best to use a hot melt adhesive or the like to ensure good adhesion.

In addition, the porous base material is formed into an
It is manufactured by subjecting it to injection molding, etc.
If it is difficult to use the fr molding/casting method, the base material formed into a film may be cut to match the tray shape, and then formed into a tray shape by heat sealing or hot melt adhesion. As for the shape of the folded bag, it is possible to have the entire surface made of porous material, or only one side (the front or back of the packaging) is made of porous base material.

Examples include one-sided fully transparent film, and those formed from opaque materials such as metallized film and aluminum foil.

The same goes for trays; both the tray and the lid can be made of porous substrates, or one can be made of a porous substrate and made of transparent film, vapor-deposited film, etc. can.

- There are no particular restrictions on the dry heat sterilization method for foods packaged with porous substrates, and all methods such as methods using hot air or radiant heat from an oven, etc., or methods using electromagnetic waves or microwaves may be applied. be able to. Among these methods, the dry heat method using electromagnetic waves or microwaves is preferable because it can intensively heat only the contents without exposing the packaging material itself to high temperatures. The dry heat temperature may be arbitrarily selected from the range of 80 to 250 degrees Celsius depending on the contents and the type of packaging material, but in order to achieve the purpose of sterilization,
It is desirable to process at a temperature of 50-250°C.

After dry heat sterilization, microbial contamination of the contents is prevented even if the container is left as is. However, if stored in a high-temperature environment, the contents will tend to undergo natural deterioration, and the moisture in the contents will evaporate through the pores of the porous substrate, resulting in dehydration. I've never done it. However, natural deterioration can be suppressed by storing cooked rice and other foods at a temperature of around 20°C under high humidity.

The present invention is roughly constructed as described above, and by utilizing the moisture permeation characteristics of the porous base material, it facilitates dry heat sterilization of packaged foods, and also minimizes spoilage caused by microorganisms during storage. It can be widely used as a simple packaging method for various foods, such as reducing the amount of food and extending its life.

Next, examples of the present invention will be shown.

Example 1 A polyester non-woven fabric whose air passage time of 100 per square inch at room temperature and normal pressure is 1 to 250 seconds per 4*1 square inch surface and a non-porous transparent polyester film with a thickness of ζ 35μ are laminated to form side edges. Peat seal on 3 sides, 15cr
Prepare a bag of nX 20 cnt.7.

Confectionery dough consisting of eggs, skim milk, flour, and sugar was put into this bag, the opening was heat-sealed, and then the bag was placed in a hot air vent and heated at 180° C. for 20 minutes. In this heat treatment step, the packaging form made of the bag material was completely unchanged from before the treatment, and no peeling of the seal portion was observed.

For comparison, we put the same yearling fabric as above in a bag made only of ordinary non-porous polyester film and sealed it.
When dry heat treatment was carried out at .degree. C. for 20 minutes, the sealed portion of the bag was peeled off and opened due to internal water vapor pressure.

Each of the packaged foods obtained above was left in a room at 35° C. and 95% R and H, and the period until mold appeared was measured. The results are shown in Table 1.

Table 1 As is clear from Table 1, seals that peel off and open during the dry heat treatment process are not effective in preventing microorganisms from entering.
After a few days, mold was generated, but when packaged in a porous bag, 9 microorganisms were prevented, and the number of days for mold growth could be extended by 1.5 to 10 times compared to the comparative example. The number of days for mold growth is increased by the number of seconds required for air to pass through the porous bag, but if it exceeds 250 seconds, the bag expands and seals are lost due to poor permeability to water vapor generated during heat treatment. A phenomenon in which parts peeled off was observed. As is clear from the above results, the more preferable number of seconds required for air to pass through the porous substrate used in the present invention is 5 to 250 seconds.

Example 2 rlT′l area per square inch, 10 at normal flow normal pressure
Two sheets of polyester nonwoven fabric with an air passage time of 1 to 250 seconds are stacked together and three side edges are heat-sealed.
A bag of 5 crn x 15 crn was produced. Commercially available castella cakes were placed in this bag, the opening was heat-sealed, and the bag was subjected to dry heat treatment at 180° C. for 10 minutes in an oven. During this heat treatment step, no peeling of the seal portion of the bag occurred. For comparison, castella was sealed in a bag made of general non-porous polyester film and heat-treated under the same conditions. When each packaged castella cake was left in a room at 35° C. and 95% (95%) and subjected to MFF3 testing for the number of days until mold appeared, the results shown in Table 2 were obtained.

The results in Table 2 are the same as those in Table 1, and the use of porous packaging bags prevents the seal from peeling off during dry heat sterilization, and significantly suppresses the spoilage of the contents due to microorganisms. be able to.

Applicant: Toyobo Co., Ltd., -1 representative Patent attorney: Ueki Kogyo Procedural amendment (voluntary) Japan Patent Office Chief Examiner Examiner from the Japan Patent Office
Tono Showa Referee
No. 3. Relationship with the case of the person making the amendment Name of the patent applicant: 112-8-1 Dojihama 2-chome, Kita-ku, Osaka
(3) 6) Toyobo Co., Ltd. Representative Maki Uno 4th Director Postal code 530 Address 2Tl+3-7 Yumi Dojima, Kita-ku, Osaka Nnko Hill Telephone Osaka (06) 343-2325 (Representative) Showa Year Month 11 ( (Delivery date) 6. Subject of amendment Column 7, "Detailed description of the invention" in document M Contents of amendment, 1, (1) "The gist of the song exists" in line 1θ of page 8 of the specification. "For the number of seconds required for air to pass in the present invention, please refer to JIS-P-8117C paper and paperboard transparency
JC degree test method] The value is the measured value. ''(I-
One piece inserted.

(2)

Claims (1)

[Claims] (1) 1oo per square inch of area at normal temperature and normal pressure
A method for producing a packaged food, which comprises packaging the food with a porous base material in which the number of seconds required for cr- air to pass through is 1 to 250 seconds, and then subjecting the food to dry heat sterilization at 80 to 250°C.