Last update:
28-Dec-2007

Freezing is the prevailing method of preserving high quality in food. Freezing of food inhibits the growth of microorganisms; it reduces their numbers but does not destroy them. The pathogens that survive the freezing procedure constitute a threat to the consumers. In addition, the toxins produced by the pathogens are even less affected by freezing. The survival mechanisms of the microorganisms at low temperatures are not well known. Survival depends on the category of the microbe, the range of freezing, the procedures of freezing and thawing, the type of food and the substrate composition. The Clostridia and bacterial spores are extremely resistant to freezing and storage at subzero temperatures. Gram-positive bacteria are generally more resistant than Gramnegative bacteria to freezing. Viruses and fungi are also resistant to freezing. Some pathogens such as Listeria, Campylobacter, Salmonellae and viruses may cause epidemic outbreaks. Food and water should be deprived of pathogens before their freezing procedure. Freezing, thawing and processing of food should be conducted according to hygiene standards.

Key words: Food freezing, Food born diseases, Pathogens, Public health, Survival of microbes.