The coliform group. I. The boric acid lactose broth reaction of coliform IMViC types.

Several methods have been suggested for the accurate, rapid, and convenient detection and enumeration of Escherichia coli in potable waters, stream samples, sewage, and in certain food products. The first of these procedures was described by Eijkman who proposed a "fecal coli" test that he believed differentiated between coliforms from the gut of warm-blooded animals and strains originating from cold-blooded ones. The method was based on the assumption that only fecal types of coliforms from warm-blooded animals could grow in glucose broth at 46 C with the production of gas. Twenty-five years later a close relationship between the positive Eijkman reaction and indole production was observed by Leiter (1929) and he suggested that the combination of the two positive tests was practically specific for E. coli. Many procedures have been proposed which claim to have provided a more suitable environment for the growth of E. coli and at the same time to have suppressed to a large degree the growth of other coliform types along with the majority of noncoliform bacteria. Most of the procedures have required the addition of