(1) Tinplate empty tank containers should be tight, especially for double crimping and resistance welds, which should meet the standard requirements. Semi-automatic resistance welding machines should not be used. The quality of the sealant in the crimping part should be excellent, and the position and thickness of the glue should be accurately met to the standard requirements. The whole process of can making should pay great attention to avoid scratching or scratching the board. Before the canned food factory seals, it should be strictly checked whether the can body is damaged or not, even if there is a slight bump, it should be removed to ensure that the canned food meets the sealing requirements.
The principle of canned food preservation relies on container sealing, moderate sterilization, and does not require or allow the addition of any preservatives. The finished product is commercially sterile and can be stored at room temperature for a long time. Therefore, canned foods have very strict requirements on the sealing of containers. The container is an inseparable and important part of canned food. It should be absolutely sealed. The air and microorganisms outside the tank cannot invade the tank, ensuring that the canned food will not be subject to secondary pollution and spoilage.
(2) Raw and auxiliary materials used in canned foods should be fresh and thoroughly cleaned. Special attention must be paid to shortening the processing time of semi-finished products as much as possible. The pre-cooking time of raw materials should not exceed 2.5 hours, and the sterilization time of cans should not exceed 30 minutes. At this time, bacteria can multiply and the number of bacteria can increase by several tens to hundreds of times. The more bacteria, the longer the sterilization time required for the same temperature; the more bacterial spores, the higher the temperature required for sterilization and the longer the sterilization time.