ENH 222 Lecture Notes - Lecture 4: Osmotic Pressure, Nitrogen Fixation, Gut Flora

• School: Ryerson University
• Department: Environmental Health
• Course: ENH 222
• Professor: Melissa Moos

Document Summary

Growth: physical requirements: temperature, minimum growth temperature, optimum growth temperature, maximum growth temperature, most microbes grow well in temperature that humans favour, some prefer extreme temperature. Found in evry cold environments (north pole, ocean depths: seldom cause disease or food spoilage. Psychrotrophs: grow between 0 c and 20-30 c, pseudomonas spp, cause food spoilage, refrigeration slows down microbial growth & food spoilage. *when putting rice in fridge make sure to put it in a flat tray otherwise bacteria can grow in a pan. Mesophiles (cid:498)middle-loving(cid:499: optimum growth temperature 25-40 c, most common group of microbes, microbes commonly associated with food spoilage, human pathogens(may be food borne, host adapted to body temperature of mammals 37c, salmonella, listeria etc. Thermophiles (cid:498)heat loving(cid:499: many can"t grow below (cid:886)(cid:887) c, optimum growth temp 50 - 60 c, adapted to live in sunlit soil, compost piles, hot springs, have unusually heat resistant endospores.