ABSTRACT
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. Sterilization procedures involve the use of heat, radiation, or chemicals, or physical removal of cells. The sterilization process consists of four distinct stages. First, the product must be heated to a temperature of 110 to 125°C to ensure sterilization. After this, 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 a reduction in the temperature gradient. Next, the product must be held at this temperature for a certain period of time to ensure a predetermined sterilization value designated by Fo. Finally, the product has to be cooled, mainly to arrest further heat treatment and to avoid overcooking [1]. The basic principles of sterilization technology as applied to food processing are [2]:
The processed product must be free from microorganisms capable of producing food poisoning toxins and those microorganisms which cause food spoilage during product shelf life, until it is consumed.
Clostridium botulinum spores are capable of growing in low-acid (pH >4.6) products during storage and hence must be heat treated to the equivalent of at least 121.1°C for 3 minutes (an Fo value of 3) to achieve a 12-decimal reduction of the microorganism.
The processing conditions should be applied to the slowest-heating point referred to as “cold point.” This facilitates the assumption that, when the slowest-heating part is sterilized, by exposing it to the required time–temperature profile, the rest of the product will be sterilized.
