ENH 222 Study Guide - Final Guide: Triclosan, Bacon, Bacteriostatic Agent
19 Apr 2018
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Lecture 8: describe patterns of microbial death caused by microbial control agents. Bacterial populations subjected to heat or antimicrobial chemicals usually die at a constant rate. Such a death curve, when plotted logarithmically, shows this constant death rate as a straight line. Time to kill a microbial population is proportional to the number of microbes. Microbial species and life cycle phases (i. e. endospores) have different susceptibilities to physical and chemical controls. Organic matter may interfere with heat treatments and chemical control agents. Moist heat is to disinfect, sanitize, sterilize and pasteurize, kills cells by denaturing proteins and destroying cytoplasmic membranes. 3 procedures involve moist heating: boiling, autoclaving and pasteurization. Dry heat is a type of boiling which requires high temp for longer times than moist heat because it requires at least 16 hours to sterilize. Dry heat is an effective sterilizing agent because it denatures proteins and fosters the oxidation of metabolic and structural chemicals.
