| influence of environmental stress on enumeration of indicator bacteria from natural waters. | the problems associated with recovery of pure cultures of escherichia coli and streptococcus faecalis from stream environments were examined utilizing membrane filter chambers. it was observed that upon exposure to the aquatic environment a significant proportion of cells lost their ability to produce colonies on a selective medium, yet retained this capability on a nutritionally rich, nonselective medium. discrepancies in colony-forming units between nonselective and selective media indicated t ... | 1975 | 803815 |