According to the study, there are many factors that affect the sterilization effect of cans, such as the degree of contamination of the food before sterilization, food ingredients, heat transfer, and the initial temperature of the cans.
1. The degree of contamination of food before sterilization
From raw material processing to canning sterilization, food will be subject to different degrees of microbial contamination. The higher the contamination rate, and the longer the time required for sterilization at the same temperature.
2. Food ingredients
(1) Canned foods contain sugar, salt, protein, fat and other foods that can affect the heat resistance of microorganisms.
(2) Foods with high acidity are generally sterilized at lower temperatures and for shorter time.
3. Heat transfer
When heating sterilization of canned goods, the main mode of heat transfer are conduction and convection.
(1) The type and shape of canning containers
Tinned thin steel cans transfer heat faster than glass cans, and small cans transfer heat faster than large cans. The same volume of cans, flat cans than short cans heat transfer faster
(2) Types of food
Fluid food heat transfer is faster, but sugar liquid, brine or flavoring liquid heat transfer rate with its concentration increases and decreases. Solid food heat transfer rate is slow. Heat transfer of the block large cans and canned tightness is slow.
(3) Sterilization pot form and cans in the sterilization pot
Rotary sterilization is more effective than static sterilization, and the time is shorter. The heat transfer is relatively slow because cans in the sterilization pot away from the inlet pipeline when the temperature in the pot has not reached balance.
(4) The initial temperature of the can
Before sterilization, the initial temperature of the food in the can should be increased, which is important for cans that do not easily form convection and slow heat transfer.
