The primary control for in foods is maintaining temperatures that C perfringens prevent multiplication of vegetative cells in cooked foods. The optimum growth temperature for is generally between 43°C to 47°C. C. perfringens Because of its fast doubling time, cooked foods prepared in advance need to be cooled rapidly to limit the time at these temperatures. Clause 7(3) of Standard 3.2.2 of the Code (Australia only**) specifies cooling requirements for cooked potentially hazardous foods which require cooling from 60°C to 21°C to be achieved within 2 hours*. Cooling from 21°C to 5°C should occur within a further 4 hours. Once cooled, cooked foods should be stored at 5°C or below. Reheating previously cooked foods also needs to be rapid to minimise the time the food is kept at optimal growth temperatures. Reheating to above 70°C will kill vegetative cells of C. perfringens present. pH and water activity The growth of C. perfringens is inhibited pH 5.5 and the minimum water activity for growth is 0.97. * Standard 3.2.2 provides for an alternative cooling process to be used where it can be demonstrated that the microbiological safety of the food will not be adversely affected. **Similar time-temperature requirements for the cooling of foods are also included in New Zealand legislation. Resources J & Bodnaruk, P (2003) Clostridium perfringens. Ch 15 In: Hocking AD (ed) Foodborne microorganisms of public health significance. 6th ed, Australian Institute of Food Science and Technology (NSW Branch), Sydney, p479-542 (1996) Microorganisms in Foods 5: Microbiological specifications of food pathogens. Chapman & Hall, London. http://www.foodsafety.govt.nz/elibrary/industry/Clostridium_Perfringens-Associated_With.htm Listeria monocytogenes Description Listeria monocytogenes is a Gram-positive, forming bacterium that is widespread in the natural environment and carried by many domestic and wild animals. It has been isolated from soils and vegetation, animal feeds such as silage, as well as surface and marine waters as a result of contamination from sewerage or run off.
The primary control for C perfringens in foods is maintaining temperatures that prevent multiplication of vegetative cells in cooked foods. The optimum growth temperature for C. perfringens is generally between 43°C to 47°C. Because of its fast doubling time, cooked foods prepared in advance need to be cooled rapidly to limit the time at these temperatures. Clause 7(3) of Standard 3.2.2 of the Code (Australia only**) specifies cooling requirements for cooked potentially hazardous foods which require cooling from 60°C to 21°C to be achieved within 2 hours*. Cooling from 21°C to 5°C should occur within a further 4 hours. Once cooled, cooked foods should be stored at 5°C or below. Reheating previously cooked foods also needs to be rapid to minimise the time the food is kept at optimal growth temperatures. Reheating to above 70°C will kill vegetative cells of C. perfringens present. pH and water activity The growth of C. perfringens is inhibited pH 5.5 and the minimum water activity for growth is 0.97. * Standard 3.2.2 provides for an alternative cooling process to be used where it can be demonstrated that the microbiological safety of the food will not be adversely affected. **Similar time-temperature requirements for the cooling of foods are also included in New Zealand legislation. Resources J & Bodnaruk, P (2003) Clostridium perfringens. Ch 15 In: Hocking AD (ed) Foodborne microorganisms of public health significance. 6th ed, Australian Institute of Food Science and Technology (NSW Branch), Sydney, p479-542 (1996) Microorganisms in Foods 5: Microbiological specifications of food pathogens. Chapman & Hall, London. http://www.foodsafety.govt.nz/elibrary/industry/Clostridium_Perfringens-Associated_With.htm Listeria monocytogenes Description Listeria monocytogenes is a Gram-positive, forming bacterium that is widespread in the natural environment and carried by many domestic and wild animals. It has been isolated from soils and vegetation, animal feeds such as silage, as well as surface and marine waters as a result of contamination from sewerage or run off.
Compendium%20of%20Microbiological%20Criteria.docx