Steam sterilization is divided into:
Low high temperature long-term sterilization method: The sterilization temperature of this method is 121 ℃, the steam pressure is 1.4kg/c ㎡, and the sterilization time is 30 minutes.
Sub high temperature short-term sterilization method: The sterilization temperature of this method is 132 ℃, the steam pressure is 3.2kg/c ㎡, and the sterilization time is 5 minutes.
High temperature instant sterilization method: Heating temperature is 135-210 ℃; The heating time is 2-8S; the sterilization process in which the product meets the pharmacopoeia sterility requirements after heating is called UHT sterilization. Powder sterilization is a sterilization method that uses heat exchange or direct steam heating for sterilization, followed by rapid cooling. This method has high sterilization efficiency and minimal physical and chemical changes in the material.
In the 1960s, it was successfully used for sterilization of milk. Milk was heated to 80 ℃ within 15-20 minutes, and then rapidly increased to 140-150 ℃ for about 5 seconds. The milk was then rapidly cooled to room temperature within 15-20 seconds. After powder sterilization, milk can be preserved for more than six months at room temperature without any preservatives. Due to its short heating time, it not only kills all bacteria, but also preserves the original color, flavor, and nutrients of milk.
The principle and process of high-temperature instant sterilization of powder raw materials and high-temperature sterilization of milk liquid are consistent. However, due to the differences and disparities in their physical properties, there are significant differences in the specific details, sterilization equipment used, and requirements for steam heat sources.
Generally speaking, there are the following requirements for high-temperature instant sterilization equipment for powder raw materials:
1. During the entire sterilization process, there must be no clumping or adhesion of raw materials.
2. The equipment should be sealed, and the sterilized raw materials should not have secondary contamination.
3. The raw materials need to be heated to above 150 ℃ in an instant, and the heating should be uniform and consistent.
4. Once sterilization is complete, immediately cool to room temperature to reduce the loss of efficacy of the original powder.
To achieve the above requirements, the heat source used for high-temperature instant sterilization of powder raw materials must be superheated steam.