Comparison of MacConkey broth, Teepol broth and glutamic acid media for the enumeration of coliform organisms in water

SUMMARY Oxoid dehydrated MacConkey broth was compared with laboratory prepared MacConkey broth, Teepol broth and three modifications of glutamic acid media, by participants in eleven laboratories. A variety of chlorinated and unchlorinated water samples were used. The Oxoid MacConkey broth was shown to be a satisfactory standard for comparison. Teepol broth was found to be a satisfactory alternative to MacConkey broth. Gray's improved glutamate medium was shown to be the best of the glutamate media and it gave results superior in most respects to MacConkey broth. In particular more Escherichia coli were obtained as well as more coliform organisms. Organisms surviving marginal chlorination were recovered more readily. Growth was sometimes slower than in MacConkey broth but this could possibly be improved by closer attention to pH adjustment and mineral composition.