POOR SPECIFICITY OF M-ENDO AND M-FC CULTURE MEDIA FOR THE ENUMERATIONOF COLIFORM BACTERIA IN SEA-WATER

Traditionally coliform bacteria have been used as indicators of the sa nitary quality of recreational water. The specificity of the widely us ed media for the detection and enumeration of total and faecal colifor ms from sea water samples, i.e. m-Endo and m-FC respectively, was eval uated. The effectiveness of the O-nitrophenyl-beta-D-galactopyranoside and cytochrome oxidase activities for the confirmation of the colonie s has also been studied. The high percentages of non-coliforms, 21.9% on m-Endo and 27.7% on m-FC, after identification of the presumptive t otal and faecal coliform isolates to species level, indicated that the se media cannot be considered specific. The biochemical tests were sho wn to be useful for excluding oxidase-positive, non-coliform colonies. A revision of the definition of faecal coliforms is suggested.