Principles of food canning
Unlike pasteurized “cooked” meat products where the survival of heat resistant microorganisms is accepted the aim of sterilization of meat products is the destruction of all contaminating bacteria including their spores. Heat treatment of such products must be intensive enough to inactivate/kill the most heat resistant bacterial microorganisms, which are the spores of Bacillus and Clostridium . In practice, the meat products filled in sealed containers are exposed to temperatures above 100°C in pressure cookers. Temperatures above 100°C, usually ranging from 110-121°C depending on the type of product, must be reached inside the product. Products are kept for a defined period of time at temperature levels required for the sterilization, depending on type of product and size of container.
The sterilization process in the canned product can be subdivided into three phases .By means of a heating medium (water or steam) the product temperature is increased from ambient to the required sterilization temperature. This temperature is maintained for a defined time. In the temperature in the can is decreased by introduction of cold water into the autoclave.
Autoclaves or retorts
In order to reach temperatures above 100°C (“sterilization”), the thermal treatment has to be performed under pressure in pressure cookers, also called autoclaves or retorts.