FOS 3042 Lecture 8: Module 8 part 2FOS3024
16 Feb 2017
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Conti microbial heat resistance: thermal death time curve. Temp increases to reduce heat time by 1 log. Temp decreases to increase heating time by 1 log cycle or 90% Temperature change required to destroy 90% of the microbial population. Or reduce by a factor of 10. Refers to the degrees fahrenheit required for the thermal destruction curve to traverse one log cycle. Relationship between time and temperature: microbial heat resistance. = to # of minutes at 121c to destroy a specific number of organisms. 1 min at 250f = f0 of 1. F=3 target: types of heat treatment, types of heat treatment. Commercially sterile foods are free of pathogenic organisms and their spores. Relationship between a microorganism growth and heat. Logarithmic or exponential: margins of safety. Don"t know which or how many organisms. Shoot for f>>3: d, z, f. =time at a given temp: low acid foods. Most vegetables and meats: high acid foods.
