For some canned products they are heated for up to one hour. All micro-organisms are killed during this process. After sterilisation the product is free of germs and, if stored correctly, have a shelf life of several years.
Classical sterilisation treatments are subdivided into two categories: sterilisation by heating (thermal processing) and sterilisation without heating (non-thermal processing).
Thermal processing is widely practiced in spite of some problem such as that the process might reduce nutrition or deterioration the quality of foods.
Non-thermal processes include high pressure processing, pulsed electric fields, ultraviolet radiation, food radiation, chemical treatments, and use of magnetic fields.
Thermal processing is further divided into two categories as in-container sterilisation and aseptic sterilisation.
Food sterilisation
