Sterilization of packaging containers (or materials)

If only the bacteria of the packaged product are killed and the containers, materials and environment in contact with them are not sterilized, there is still no guarantee that the packaged items will not be invaded by microorganisms, so the aseptically packaged packaging containers (or materials) must also be Since it does not adhere to microorganisms and has a barrier property against gas and water vapor, it is also necessary to sterilize the packaging container (or packaging material) before the aseptic filling of the packaged product, and the packaging container (or packaging material) is destroyed. Bacteria usually have drug sterilization, UV sterilization technology and so on.
I. Drug Sterilization Technology The bactericide used for drug sterilization must be bactericidal and non-corrosive to the equipment. During the sterilization process, no harmful substances will be generated. At the same time, there will be less residual drug in the package material.
At present, the most commonly used insecticide is hydrogen peroxide, commonly known as hydrogen peroxide. The bactericidal power of hydrogen peroxide is related to its concentration and temperature. The higher the concentration, the higher the temperature and the better the bactericidal effect. The concentration of hydrogen peroxide commonly used for sterilization is 25% to 30%, and the temperature is 60 to 65°C. Sterilization with hydrogen peroxide should be combined with heat treatment, as hydrogen peroxide evaporates from the surface of the material with greater bactericidal efficacy.
Hydrogen peroxide is used to sterilize the packaging container (or packaging material) by immersing the packaging container (or packaging material) in hydrogen peroxide or by spraying hydrogen peroxide on the packaging container (or packaging material). They are then heat-radiated so that the hydrogen peroxide remaining on the packaging container (or packaging material) is completely evaporated together with the hot air and decomposed into harmless water vapor and oxygen.
Second, UV sterilization technology UV sterilization effect and UV wavelength, irradiation and irradiation time, the wavelength of 250 ~ 260nm is the strongest.
The survival rate of microorganisms after ultraviolet irradiation can be expressed by the following formula:

Where: S--bacterial survival rate P--bacterial survival rate after UV irradiation P0--number of bacteria before UV irradiation E--effective radiation intensity t--irradiation time Q--Set S segment to 1 /E=36.8%, the required radiation dose (effective irradiance x exposure time)
From the above, the sterilization of microorganisms is determined by the amount of radiation that accumulates with the effective irradiance and irradiation time.
The sterilization mechanism of ultraviolet rays is mainly due to chemical changes in the nucleic acids in the microorganisms after ultraviolet irradiation, which causes metabolic disorders and thus loses its ability to proliferate. The use of ultraviolet sterilization must also pay attention to the following:
1, to prevent foreign body structure Due to low UV energy, poor penetration, so only limited to the surface sterilization. Bacteria on the surface of the packaging container (packing material), such as dust and foreign matter, cannot be killed. Therefore, as a food container for ultraviolet sterilization, the packaging material must pay particular attention to the avoidance of the adhesion of foreign materials, especially plastic products, in order to avoid the adhesion of dust and foreign substances due to static electricity.
2. Management of Primary Bacteria As shown in Fig. 7-1, when the spores of Bacillus subtilis were below 104/100 cm2, the number of surviving spores decreased linearly with the extension of UV irradiation time. When the initial bacterial count of Bacillus subtilis was more than 104/100cm2, the UV irradiation time increased by 3s, 5s, 10s, and the number of surviving spores did not decrease much. This phenomenon is called tailing phenomenon. The important factor that causes this phenomenon is the shadow effect between bacterial groups. Therefore, the packaging container (or packaging material) is sterilized by ultraviolet rays, and the pretreatment before sterilization is very important. The number of primary bacteria directly affects the sterilization effect. If the management is strict, the number of primary bacteria in the packaging container (or packaging material) is small, the safety rate of sterilization is high, and sterilization conditions can be eased.

The effect of ultraviolet sterilization is not only affected by the irradiation distance and the irradiation time, but also related to the effective irradiation degree of the surface of the object. The illuminance of a high-performance ultraviolet sterilizer is degraded by the effects of aging of the UV lamp, contamination of the bulb and the reflective surface, dirt, smoke, dust, and the like.
In addition, according to the characteristics of the packaging container (or material), various sterilization methods such as high temperature, microwave, far infrared, and ionizing radiation can also be used to sterilize the packaging containers and materials.