The methods of beverage sterilization include physical sterilization and chemical sterilization. Chemical sterilization uses hydrogen peroxide, ethylene oxide, sodium hypochlorite and other fungicides. Due to the influence of chemical residues in chemical sterilization, contemporary food sterilization tends to physical sterilization. Physical sterilization can be divided into hot sterilization and cold sterilization. Thermal sterilization can be divided into thermal sterilization, dry-hot sterilization, microwave sterilization and far infrared heating sterilization. The cold sterilization methods are divided into ultraviolet radiation sterilization, ionizing radiation sterilization and freezing sterilization. Among the wet-hot sterilization methods, there are pasteurization, high temperature short-time sterilization and ultra-high temperature instantaneous sterilization. Paseurization is a low-temperature and long-time sterilization method. The sterilization temperature is lower than 100 C and the holding time is 30 minutes. High temperature short-time sterilization (HTST), the sterilization temperature is generally below 100 degrees Celsius, such as milk HTST sterilization temperature is 85 degrees Celsius, maintain more than 15 seconds. Ultra-High Temperature Instantaneous Sterilization (UHT) method, the sterilization temperature is above 120 C, only a few seconds. HTST and UHT sterilization not only have high efficiency, but also have better structure, appearance, nutrition and flavor preservation than other sterilization methods. There are many kinds of beverage sterilization equipments developed according to the above sterilization methods. There are three kinds of beverage sterilization equipments according to the morphology of the treated materials.
1. Sterilization equipment for canned beverages Canned beverages and bottled beverages with packaged containers. Sterilization equipment for handling such materials can be divided into atmospheric sterilization equipment and pressurized sterilization equipment according to different sterilization temperatures. The sterilization temperature of atmospheric sterilization equipment is below 100 C, which is used to sterilize beverage products with pH less than 4.5. Canned sterilizing equipment designed with pasteurization principle belongs to this category. Pressure sterilization equipment is generally carried out in a sealed equipment, the pressure is greater than 0.1 MPa, and the temperature is usually about 120 C. Atmospheric and pressurized sterilization equipment can also be divided into intermittent and continuous operation. According to the different heat sources used in sterilizing equipment, it can be divided into direct steam heating sterilizing equipment, water heating sterilizing equipment, flame continuous sterilizing machine and so on.
2. Bactericidal equipment for fluid drinks. Fluid drinks refer to unpackaged dairy products, juices and other materials. There are direct and indirect sterilization equipments for handling this kind of material. Direct sterilization is carried out by spraying neatly and directly into the material. Indirect heat exchanger is used to sterilize beverage by heat exchange between plate and tube.
3. Physical sterilization equipment using electromagnetic wave. This kind of sterilization equipment uses microwave, far infrared and ultraviolet radiation to heat and sterilize. It is a promising sterilization equipment.
In beverage processing, sterilization is a very important link. There are some differences between beverage sterilization and medical and biological sterilization. There are two meanings of beverage sterilization: one is to kill pathogenic bacteria and spoilage bacteria contaminated in beverages, destroy enzymes in foods, and make beverages have a certain shelf life in certain environments, such as sealed bottles, cans or other packaging containers; the other is to protect the nutritional components and contents of beverages as much as possible in the sterilization process. Flavor. Therefore, sterilized beverages are commercially sterile.