JPS6135827B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for sterilizing foods using ozone. Food sterilization methods include heat sterilization, chemical sterilization, and radiation sterilization, which are used depending on the type and characteristics of the food. Among these sterilization methods, gas sterilization, which is a type of chemical sterilization, is cold sterilization and can be applied to foods that are sensitive to heat, and unlike other sterilization agents, it does not require moisture and can be applied to dry foods. It has the characteristics of There are several types of gases that can be used for sterilization, but ozone has a sterilizing effect and is ultimately decomposed and rendered harmless, making it an advantageous food disinfectant. be. However, although the conventional ozone sterilization method achieves the purpose of sterilization, it also causes unfavorable food quality phenomena such as oxidation of oil in food, generation of off-flavors, and discoloration of pigments, and the sterilization operating conditions are insufficient. The drawback is that it is extremely difficult. For this reason, food sterilization methods have not yet been developed to a practical scale, and they have only been applied to sterilize water, etc., which are not likely to cause any harmful effects. On the other hand, in recent years, a large number of simply packaged foods have been sold mainly in supermarkets, but these foods come in a variety of varieties and cannot be packaged mechanically aseptically. There are many foods for which heat sterilization is not appropriate, and packaging materials that are heat-resistant are not used. Considering this situation, there have been more expectations than ever before for the emergence of a sterilization method that allows cold sterilization and does not have the disadvantages seen in conventional methods. Therefore, the inventors of the present invention have conducted intensive research to resolve the drawbacks of conventional ozone sterilization methods, and have found that if ozone is brought into contact with food through a breathable film rather than directly, there will be no deterioration in the quality of the food. They discovered that it is possible to sterilize without causing any disease, leading to the completion of the present invention. That is, the present invention is a food sterilization method characterized by interposing a breathable film between the food and ozone and allowing the ozone that passes through the breathable film to come into contact with the food. The sterilization method of the present invention can be applied to all foods contaminated with microorganisms during production, transportation, sales, etc. In particular, the method of the present invention is useful for sterilizing foods that cannot be heat sterilized, such as foods that are simply packaged with breathable film. Examples of simply packaged foods include fruits, vegetables, fish, meat,
Examples include fresh foods such as livestock meat, grains such as rice, barley, and beans, meat paste products, seafood paste products, noodles, pickles, and various processed foods such as tempura and fries. The breathable film used in the present invention is not particularly limited as long as it is used for ordinary food packaging. For example, any breathable synthetic film such as polyethylene, polypropylene, polystyrene, or polyvinyl chloride can be used. Also, the thickness of the film is usually about 0.005 to 0.04
mm, preferably about 0.008 to 0.03 mm, and particularly preferably about 0.01 to 0.02 mm. Furthermore, there is no particular restriction on the air permeability of the film as long as ozone can pass through it, but it is usually preferable that the film has an oxygen permeability of about 50 to 500 (cc/m ² hr) (ASTM measurement method, 20°C). . Next, in the method of the present invention, instead of bringing food and ozone into direct contact as in the conventional method, a breathable film is interposed between the food and ozone, and the ozone that passes through the breathable film is brought into contact with the food. It is carried out with A specific contact method involves wrapping the food in a breathable film and placing the packaged food together with a certain amount of ozone in a container made of non-breathable material (e.g., a laminated non-breathable plastic bag, It may be sealed in a cardboard box (such as a cardboard box), or it may be left in a sealed room or container with an ozone atmosphere and brought into contact with it. Alternatively, a method may be adopted in which a breathable film is filled with ozone and left in a closed room or container together with unpackaged food, so that the food and ozone come into contact with each other. The ozone used for sterilization in the present invention may be produced by a method known per se, for example, ozone generated by silent discharge in the air. The amount of ozone used is determined by taking into account the type of food, the contact time with the food, the material and permeability of the breathable film, but it is usually about 0.05 to 0.5 mg, preferably about 0.05 to 0.3 mg per gram of food. Selected by range. The time required for sterilization using the method of the present invention depends on the air permeability of the film,
The process may vary depending on the type and shape of the food, the contaminating microorganisms, etc., but the point is that ozone can pass through the breathable film, uniformly contact the food, and sterilize the food. Usually, the purpose is achieved by leaving a certain amount of ozone for about 3 hours or more after encapsulating it. This sterilization time can be determined by using the transportation time, storage or storage time, etc. during the food distribution process. In other words, in the case of many foods, the time required for transporting or storing them is 4 to 20 hours.
Foods can be sterilized by the method of the present invention using this time. The sterilization method of the present invention can easily sterilize even foods to which ordinary heating or chemical sterilization methods cannot be applied. For example, most of the various types of simply packaged foods displayed in supermarkets are impossible or undesirable to heat sterilize due to the packaging material and food usage. The purpose of sterilization can be achieved safely without compromising the quality of the product. Another disadvantage of the conventional method of bringing ozone into direct contact with food is that the food itself is subject to the harsh oxidation effect of ozone, resulting in quality deterioration, and if the amount of ozone used is reduced to avoid this, sterilization is reduced. It was hot. However, if ozone and food are brought into contact with each other through a breathable film as in the method of the present invention, these conventional drawbacks can be overcome, and ozone can be continuously supplied, so sterilization is complete. This is an extremely practical sterilization method because it also makes use of transportation and storage time. Next, the present invention will be explained in more detail using experimental examples and examples. Experimental Example 1 In order to sterilize commercially available minced beef with ozone (using a silent discharge ozone generator), the following direct contact method and indirect contact method (method of the present invention) were carried out, and the sterilization effects of both methods were evaluated. and the effects on quality were compared. ◎Direct contact method: Place minced beef in an unwrapped bag in a non-porous film tube laminated with polypropylene, EVAL, or polyethylene, enclose a certain amount of ozone shown in Table 1, and then heat the film tube with a heat sealer. It was crimped and used as a specimen. ◎Indirect contact method: Food is placed in a tray, the outside is wrapped with a breathable polyvinyl chloride film wrap (Riken Vinyl Kogyo, Riken Wrap M type), and then placed in the same non-breathable film wrapper as above. After sealing in a certain amount of ozone shown in the table, the film tube was crimped with a heat sealer and used as a specimen. After each of the above specimens was left for a predetermined period of time, the sterilization effect on general bacteria and coliform bacteria, the oxidation of fats and oils, and the flavor and appearance were evaluated. The results are shown in Table 1.

[Table] As can be seen from the results in Table 1, when ozone was brought into direct contact with minced beef, oxidation of fats and oils, deterioration of flavor, and discoloration of pigments progressed, and adverse effects on quality were observed. On the other hand, in the method of the present invention, such quality deterioration was hardly observed. Experimental Example 2 Burdock tempura produced by a conventional method was brought into contact with ozone directly in the same manner as in Experimental Example 1 and in the method of the present invention, and the bactericidal effect and influence on quality were compared. The results are shown in Table 2. As can be seen from the results in Table 2, when ozone was brought into contact with tempura using the method of the present invention, almost no deterioration in quality was observed as seen in the direct contact method.

【table】

[Table] Example 1 After thawing frozen mongo squid, a piece (200 to 300 g) processed for sashimi was packed in a tray in a breathable polyvinyl chloride bag wrap (manufactured by Riken Vinyl Kogyo,
After packaging with Rikenlap M type), 20 packs in 5 stages and 4 rows are packed in a plastic bag with a zipper that has been set in advance in a cardboard box.An ozone introduction tube from an ozone generator is set at the bottom of the plastic bag. Immediately after sealing in ozone at a concentration of 0.1 mg per gram of sashimi, the chuck was closed, and the lid of the cardboard box was sealed with craft tape.
After storing this product at 7°C for 18 hours, it was opened and its flavor, general bacteria count, and quality were compared with a control group in a similar packaging without ozone. Incidentally, yellowtail sashimi was also sterilized using the same method.

【table】

[Table] Example 2 6000g of special grade pollock sauce, 120g of salt, 60g of sodium glutamate, 300g of potato starch
G, ice water 1200g, mirin 60g, sugar 60g, crab flavor 60g mixed as usual.
did. The obtained Surimi was formed into a plate shape with a thickness of about 2 cm, and after being heated at 40℃, food coloring (red) was applied.
was applied to the surface and steamed for 45 minutes at 85℃, then 1mmφ
It was cut into small pieces to produce a fish paste product commercially known as crab legs. After packing 200g of this into trays and wrapping them in breathable polyvinyl chloride wraps (Mitsui Toatsu Chemical's Hi-Lap V type), they were placed in 5-pack plastic bags with zippers that had been set in a cardboard box in advance.
An ozone inlet tube from an ozone generator packed in 3 rows of 15 packs was set at the bottom of a plastic bag, and 0.15 mg of ozone per 1 g of this fish paste product was sealed, immediately checked, and the cardboard box was sealed with the lid closed. Next, after storing at 10°C for 24 hours, the cardboard box and plastic bag were opened and the individually packaged items were taken out and stored at 10°C to examine their storage conditions. In addition, by the same method, Chikuwa (fried fish product)
It was also sterilized.

[Table] Example 3 After heating the bone-cut conger meat at 80℃ for about 5 minutes, it was rapidly cooled in ice water and placed in a tray in a breathable polyvinyl chloride bag wrap (RIKEN VINYL, Riken Wrap M type). The wrapped items were packed in glued plastic bags that had been set in advance inside a cardboard box, in 5 rows and 3 rows, for a total of 15 packs.The inlet tube from the ozone generator was set at the bottom of the plastic bag, and ozone was applied to 1g of conger meat. It was sealed at a concentration of 0.1 mg. Next, snow drying was applied to the top of the pack, the plastic bag and the lid of the cardboard box were sealed, and after storage at 7°C for 12 hours, the quality was compared with a control product similarly packaged without ozone treatment.

[Table] Example 4 Cut cabbage and cucumber for vegetable salad, wash with water, fill about 200 g in a bag made of breathable polyvinyl chloride film (Mitsui Toatsu Chemicals, Hi-Lap M), seal the bag opening, and then seal the bag with a wide-mouth lid. These vegetables were packed in 20 bags in a plastic tank with an ozone generator and were
Immediately after filling 0.15 mg of ozone per gram of ozone, the plastic tank was sealed with a lid. This product was stored at 10°C for 12 hours, opened, and left at room temperature for 5 hours, and its quality was compared with a control product packaged under the same conditions without ozone treatment.

[Table] Example 5 Boiled beans for side dishes were prepared using a conventional method, and 200g of each was sealed in a bag made of breathable polyvinyl chloride (Riken Lap V type, manufactured by Riken Vinyl Industries). The bag was placed in a non-breathable bag laminated with polyethylene and the opening was glued. As a control, we simultaneously manufactured products without ozone encapsulated and products with ozone directly encapsulated without wrapping with a breathable film.
After storing each at 15°C for 6 days, the number of general bacteria was measured and the taste was evaluated. As shown in Table 7, the method of the present invention was found to be excellent as a method for sterilizing boiled beans.

【table】

Claims (1)

[Claims] 1. A method for sterilizing food, which comprises interposing an air-permeable film between the food and ozone, and bringing the ozone that passes through the air-permeable film into contact with the food.