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Second, infrared sterilization method and microwave sterilization method As mentioned above, microwave and infrared sterilization method is a hot-wire sterilization method, which depends on the frequency of the waves caused by the resonant friction of the packaging materials and food molecules to generate heat, and thus sterilization. In general, light with a wavelength of 4 μm or more is called far-infrared. The bactericidal effect has a great relationship with the ability of absorbing irradiated infrared rays in food and packaging materials. The greater the ability to absorb infrared rays, the higher the bactericidal effect. In general, far-infrared rays can pass through a thickness of 25mm or less of plastic film, sheet, and container wall thickness, and a thickness of more than 2.5mm has less effect due to less infiltration of infrared rays.
The food is packaged in a plastic film or plastic container and then subjected to far-infrared radiation sterilization. The effect is better. Through the far-infrared rays of the packaging material, some of the packaging material absorbs the bactericidal effect, which is particularly suitable for containing air. The food package is sterilized.
Microwave ovens have been widely used in home cooking. Microwaves, like far-infrared rays, are a kind of hot-wire sterilization. They are suitable for use in plastic packaging materials that can penetrate electromagnetic waves. They are particularly suitable for sterilizing foods containing air and can be quickly heated to 140°C. Time kills bacteria.
Third, ozone sterilization ozone has a very strong role in the killing of bacteria, if you use ozone alone, it requires a higher concentration of hydrogen peroxide, when the hydrogen peroxide concentration as high as 20% to 30%, the surface of the printing ink in the role of hydrogen peroxide Decolorization will occur. At this time, if ozone is combined with ultraviolet light to sterilize the packaging material, the concentration of hydrogen peroxide can be greatly reduced. Only 5% to 7% hydrogen peroxide can be used to effectively sterilize the material. After the hydrogen peroxide is sterilized, it should be used to blow off the ozone remaining on the surface of the film with hot air. The residual amount of ozone on the packaging film should be 0.01ppm or more according to the US FDA standard, and the amount of H2O2 in the food should be less than 100ppm. Ozone sterilization can only be used under packaging materials and cannot be used directly on food packaging. This is the drawback of ozone sterilization. It is mainly used in Fetrapar's sterile paper/plastic/aluminum multi-layer composite soft canned beverage packaging.
Fourth, the co-extruded heat sterilization method This aseptic packaging was invented by the French company erca, it is the use of the production of co-extruded multilayer film in the process of high heat, aseptic packaging in the sterile room, the co-extruded Out of the two layers on the inner layer of poor compatibility to peel off, exposing a clean sterile inner layer to fill the food forming sealed bags.
Fifth, ultra-high temperature short-term sterilization method This method is commonly used in the sterilization of high-viscosity liquid foods. Such as: milk, ketchup, sugar sauce and other packaging, in a stainless steel autoclave container, under high pressure so that the milk with high pressure steam above 150 °C mixed for about 20s, disinfection, and then into the vacuum chamber, The excess water evaporates out, reaches the original milk concentration, enters the sterile room, and is packaged in a sterile package. At present, the packaging film of milk in China is mainly composed of a coextruded composite film with a thickness of about 15 μm, which can be stored for 1 month at room temperature. If the coextruded composite film contains eval or PVDC with a high barrier, it can be left for 3 months at room temperature. , If you use aluminum / paper / plastic multilayer film packaging, can be placed at room temperature for more than 6 months.
Aseptic packaging is the main packaging method for food packaging in the future. It plays a significant role in improving the food preservation period and prolonging the food application period. It is worth the packaging industry to vigorously develop and produce.
Aseptic packaging technology and packaging materials (below)
In addition, when the light is illuminated, the presence of oxygen is conducive to the improvement of the bactericidal effect. For example, Bacillus cereus (Bacillus sp.) spores in the air, the sterilization effect is more than doubled in the N2 gas flow, Botox Ultraviolet light at 65°C. Can greatly improve the sterilization effect. Internationally, CO60 gamma ray is commonly used to sterilize packaging materials and spices, and seasonings, frozen foods, and fish and shrimp. The Yangzhou Food Factory in Jiangsu Province uses double-layer LDPE/EVA composite flexible packaging barrels equipped with EVA check valves as sterility. Packaging materials for exporting tomato sauce are bactericidal with CO60 gamma rays and have achieved good social and economic benefits. The CO60 γ-rays are already the main means of sterilizing bagin bOx.