COMPARISON OF FLUOROGENIC AND CONVENTIONAL MEMBRANE-FILTER MEDIA FOR ENUMERATING COLIFORM BACTERIA

4-Methylumbelliferyl-beta-D-galactoside and 4-methylumbelliferyl-beta- D-glucuronide were added to MacConkey broth and their diagnostic power s for total coliforms (TC) and Escherichia coli, respectively, were te sted by membrane filtration at primary isolation. Examining water samp les from different sources proved the usefulness of fluorogenic rather than reference media both as regards recovery efficiency and rapidity (possible within 12 h) of analyses. The recoveries obtained by fluoro genic and conventional tests for both TC and E. coli were correlated. Values were comparable in surface water samples, while a higher sensit ivity of fluorogenic media was observed in samples of shallow contamin ated ground water. Results seem to indicate that the use of fluorogeni c membrane filtration analysis for colimetric indicators could be favo urably considered especially for sanitary surveying of drinking water.