BIOL241 Study Guide - Final Guide: Enterobacter Aerogenes, Fecal Coliform, Coliform Bacteria
24 Mar 2015
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= numbers of fields in the 1 cm2 area / vol. of milk over 1 cm2. Results: number of bacteria in each milk sample, expired pasteurized milk > raw milk > fresh pasteurized milk. Methods: create serial dilutions of pasteurized and unpasteurized milk samples, mix dilutions with molten agar, let them solidify, then incubate. Results: number of bacteria in each milk sample, unpasteurized raw milk > pasteurized fresh milk. Background: cheese is the result of the metabolic activity of microorganisms, lactic acid-producing bacteria initiate the cheese-making process. Results: apt agar rod-shaped bacteria, emb agar rod-shaped bacteria, malt extract agar cocci-shaped bacteria. Background: food poisoning caused by enterotoxin-producing strains of staphylococcus aureus, excrete a heat stable exotoxin into the food. Ingestion of pathogenic microorganisms can grow in the intestinal tract and produce toxic substances: e. g. Salmonella infections liberation of endotoxins (lps in the outer membrane) Large numbers of staphylococci are necessary to produce food poisoning.
