NFSC 112 Lecture Notes - Lecture 19: Good Manufacturing Practice, Clarence Birdseye, Listeria Monocytogenes
15 Nov 2016
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1875 mechanical ammonia refrigeration systems invented, allowed development of commercial refrigerated warehousing and freezing. 1920"s clarence birdseye pioneered research on the following: Commercial and household refrigerators usually operate at 4. 5 - 7 c. Most foods don"t freeze until -2 c or slightly lower due to presence of solutes, such as minerals and proteins. Refers to storage temperatures below freezing: maintain food in the frozen condition. Good frozen storage generally requires temperatures of -18 c or below. Most food spoilage organisms grow rapidly at temperatures above 10 c. But some grow at temps below 0 c, as long as there is unfrozen water available. Most food pathogens do not grow well at refrigerated temperatures: however, some can grow at refrigerated temperatures such as listeria monocytogenes. Below -9. 5 c, there is no signi cant growth of spoilage or pathogenic microorganisms. Destruction of microorganisms by freezing is not complete. Refrigeration design (i. e. cooling capacity and insulation) must be taken into account.
