JPS6343075B2 - - Google Patents

Description

[Detailed description of the invention]

This invention relates to improvements in retort sterilization methods for foods and pharmaceuticals packaged in plastic containers. Conventionally, as a method for heat sterilizing food and medicine packaged in plastic containers, the food and medicine packaged in plastic containers are placed in a retort, and then a high-temperature heat sterilization medium and a pressurized medium are introduced into the retort and sterilized under pressurized conditions. A method of sterilizing by high temperature heat is generally used. To explain the above heat sterilization method in detail, after food and medicine packaged in plastic containers are placed in a retort, the air in the retort is evacuated while steam is generally fed in as a heat sterilization medium. The air is replaced with water vapor, and then the amount of discharge is reduced, and pressurized air is sent into the retort as a pressurizing medium to increase the internal pressure of the retort, and the atmosphere inside the retort is raised to a predetermined sterilization temperature of over 100℃ and a predetermined pressure. After that, the supply amount of steam and pressurized air is controlled to an appropriate supply amount, and the sterilization temperature and pressure are maintained for a predetermined period of time to complete the sterilization. However, when heat sterilization is performed using the method described above,
At high temperatures exceeding 100°C, plastics naturally have minute gas permeability, the molecular movement of water vapor or oxygen contained in the air becomes active, and the atmosphere inside the retort is under pressure. As a result, water vapor or oxygen in the retort atmosphere easily permeates the thin plastic container packaging material, and the water vapor or oxygen that permeates the packaging material and enters the plastic container causes the contents to become damaged, such as rice crackers, etc. Foods such as peanuts,
Dried products such as dried kelp have the problem of mold formation due to the intruding moisture and oxygen, especially during long-term storage. As a result of repeated research to solve this problem, the inventors have found that during the retort sterilization described above, the plastic container-packaged foods and pharmaceuticals are vacuum-packaged using a laminated packaging material containing at least one aluminum layer and heat sterilized. They discovered that the above-mentioned problems could be solved by doing so, and completed this invention. That is, the present invention provides food and pharmaceutical products packaged in plastic containers, which are housed in a retort, and then a high temperature heat sterilization medium and a pressurized medium are introduced into the retort to sterilize them by high temperature heat under pressurized conditions. Retort sterilization method for food and pharmaceutical products packaged in plastic containers, characterized in that the food products and pharmaceutical products packaged in plastic containers are sterilized by high temperature heating after being vacuum packaged using a laminated packaging material containing at least one aluminum layer. It's a method. In the present invention, specifically, foods and medicines packaged in plastic containers are those whose contents are sealed in a package called a so-called retort pouch, such as a plastic molded container or a plastic molded bag. In the present invention, the food and pharmaceutical products packaged in plastic containers are grouped in an appropriate number depending on the size of the container, vacuum-packed in a laminated packaging material containing one aluminum layer, and sterilized in a retort. Specifically, the laminated material containing one aluminum layer has an aluminum layer with a thickness of 0.010 to 0.030 mm as an intermediate layer, an inner layer of polypropylene or polyethylene with a thickness of 0.010 to 0.050 mm, and an outer layer with a thickness of 0.010 mm.
Examples include those laminated with polyethylene terephthalate or polypropylene of ~0.020 mm. Specifically, in the retort sterilization method of the present invention, first, the above-mentioned vacuum-packed food and medicine packaged in plastic containers are placed in a retort, and then steam, generally used as a heat sterilization medium, is introduced into the retort using a conventional method. Replace with internal air. Next, pressurized air is generally introduced as a pressurizing medium at an appropriate time to raise the internal pressure of the retort, and the atmosphere within the retort is brought to a predetermined sterilization temperature of over 100°C, most commonly 120°C, and a pressure corresponding to this. After that, the supply amount of steam and pressurized air is controlled to an appropriate supply amount, and this is maintained for a predetermined period of time to complete sterilization. In this invention, as separately proposed by the inventors, if the above-mentioned retort sterilization is performed using an inert gas such as nitrogen as the pressurized medium, oxygen intrusion into plastic container-packed foods and medicines can be suppressed and the preservability can be improved. Improved results can be obtained. Furthermore, even after the above-mentioned retort sterilization, foods and medicines packaged in plastic containers can be left vacuum-packaged using the above-mentioned aluminum laminated packaging material, and if this is taken out when displayed at a store, transportation, etc.
This is preferable because it also prevents moisture from entering the food and medicine packaged in plastic containers during transportation. This invention will be explained below with reference to Examples. Example A packaging material was used in which Eval (trade name) with a wall thickness of 0.015 to 0.025 mm was used as an intermediate layer, and polypropylene was laminated on both sides.
680c.c., weight 31g bottle, contents 200c.c., weight 15g cup, and multi-layer nylon wall thickness 0.5
A bottle with a size of 680 c.c., a content of 680 c.c., and a weight of 31 g was prepared. The bottles and cups were filled with an appropriate amount of rice crackers or instant ramen noodles, and then vacuum-packed with aluminum laminated packaging material, and the bottles and cups were prepared as normal bottles or cups, respectively. Next, each of the above items is subjected to normal retort sterilization at 110°C for 40 minutes using water vapor as the heating medium and air as the pressurizing medium, and then the weight of the bottle and cup still filled with the contents is The difference between the weight before sterilization and the weight before sterilization was calculated as the amount of moisture permeation.The results are shown in the table below.

[Table] As shown, when the container is further packaged with an aluminum laminated material, no infiltrated moisture is detected compared to the case where the container is only a normal container, and it is clear that the present invention is significantly superior. As is clear from the above description and examples, this invention can prevent the above-mentioned moisture or oxygen from entering due to retort sterilization, so the flavor of the contents in the retort pouch is not impaired.
In addition, the problem of easy mold formation is eliminated, and long-term storage stability is improved, making it especially suitable for retort pouches containing contents that dislike moisture or oxygen, and its industrial effects are extremely large.

Claims (1)

[Claims] 1. A method for retort sterilization of foods and pharmaceuticals packaged in plastic containers, in which the food and pharmaceutical products packaged in plastic containers are placed in a retort, and then a high-temperature heat sterilization medium and a pressurized medium are introduced into the retort and sterilized by high temperature heat under pressurized conditions. A retort sterilization method for food and pharmaceutical products packaged in plastic containers, characterized in that the food products and pharmaceutical products packaged in plastic containers are vacuum-packaged using a laminated packaging material containing at least one aluminum layer and then sterilized by high temperature heating.