Sterilization is the complete destruction or elimination of all viable organisms in/on a food product being sterilized. Sterilization destroys yeasts, molds, vegetative bacteria, and spore formers, and allows the food processor to store and distribute the products at ambient temperatures, with extended shelf life.
The sterilization process consists of four distinct stages. [Harlfinger, L., Microwave sterilization, Food Technol., 57, 61, 1992.]
First, the product must be heated to a temperature of 110°C–125°C to ensure sterilization.
Second, the product requires a few minutes to equilibrate, since the surface will be hotter than the central portion of the container causing a temperature gradient. The equilibration stage allows reduction in the temperature gradient.
Third, the product must be held at this temperature for a certain period to ensure a predetermined sterilization value designated by F0 value.
Finally, the product has to be cooled mainly to arrest further heat treatment and avoid over cooking.
A variety of retorts, still retorts, craterless retorts, and agitating retorts, are available.
