Enumeration and Identification of Heterotrophic Bacteria from Drinking Water

摘要

Various spread-plating enumeration media and procedures have been tested to determine the method of choice for the enumeration of the highest numbers of heterotrophic bacteria from chlorinated drinking waters. Dilute media, including a caseinate peptone starch medium, a dilute peptone medium, and R2A medium provided greater recoveries than the standard plate count medium currently employed. In addition, reduced temperatures of 20 degrees C and prolonged incubation periods of 14 to 28 days resulted in the highest recoveries of heterotrophic bacteria from the two, chlorinated, distribution waters examined.