Coliform Organisms in Certified Milk

Abstract

Of 2252 coliform colonies isolated from 233 samples of certified and 71 samples of producers'' raw milks 81.1% gave acid and gas in lactose and 18.9% gave acid only. 1106 confirmed strains were classified on the basis of their reactions in indol, methyl-red, Voges-Proskauer, citrate, and cellobiose mediums. Sectional distribution in certified milk was: Escherichia, 10.3%; intermediate, 32.4%; Aerobacter, 57.3%. Producers'' raw milk gave: Escherichia 9.1%; intermediate, 16.7%; Aerobader 74.2%. The percentage distribution of the sections in dust of cow barns, material from cow hides, and in human and bovine feces indicated that these were not the sources of the coliform organisms in certified milk.