MMG301 1nd Edition Lecture 19Outline of Last Lecture I. MicrobesOutline of Current Lecture II. Cardinal temperaturesIII. SterilizationIV. AutoclavingV. Pasteurization Current Lecture-cardinal temperatures-minimum: Lowest temperature at which a given organism can grow.-optimum: Temperature at which a given organism growth the fastest.-maximum: Highest temperature at which a given organism can grow.-typical growth temperature range spans 20 to 40 degrees C-microbes tolerating an extended range of temperatures: -psychrotolerant mesophiles: organisms that grow optimally between 20-40ºC, but that tolerate and can grow at colder temperatures (psycho means cold). Largely responsible for food spoilage in refrigerators (ex: the pathogen Listeria monocytogenes: minimum 1ºC; optimum 30-37ºC)-thermotolerant mesophiles: organisms that grow optimally between 20-40ºC, but that tolerate and can grow at warmer temperatures. -pasteurization: reduction of the population of undesirable microbes in a heat-sensitive liquid-not all bacteria are killed during pasteurization-pasteurization is not sterilization.-used for milk and other heat-sensitive foods (e.g., nuts) These notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.-sterilization: killing or removal of ALL living organisms and viruses from a medium or object-autoclaves sterilize with heat-usually at 121°C and 15 lb/in2-in autoclaves the high temperature kills the microorganisms-the high pressure is used to keep liquids from boiling
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