Simultaneous Determination of Coliform and Escherichia coli Indices.

Whether all members of the coliform group of bacteria should be accorded equal sanitary significance has been debated for at least a generation. English and German authorities are disposed to assign special significance to the presence of Escherichia coli, whereas it is the American practice, particularly as applied to water analyses, to consider all coliform bacteria of equal sanitary significance. The latter concept has been challenged from time to time, especially as to its applicability to various foods and, under some conditions, even to certain water supplies. With respect to foods, a strong tendency has developed to distinguish and to ascribe different sanitary significance to the presence of various species, or types, of coliform bacteria, as, for example, in the case of oysters and clams. Irrespective of which of the foregoing views one may hold, there is undoubtedly agreement that until a relatively simple, dependable, expeditious, and economical procedure for ascertaining the E. coli and coliform indices, respectively, are available, the data necessary to evaluate properly the sanitary significance of the presence of various species, or types, of the coliform group of bacteria will not be forthcoming. This report will deal with a procedure for the selective enrichment and detection of E. coli in the presence of other coliform bacteria in water, and this should be equally applicable to other foods.