[Culturing of chlorine-damaged E. coli bacteria using the membrane filteration technic].

The number of chlorine-impaired E. coli organisms obtainable with the aid of the membrane-filtration-Endo-agar-method is so reduced that this method cannot be considered equivalent to liquid enrichment. Notwithstanding the well documented difficulties that arise from differences between batches of the same filters e. g. from problems to assure their standardization, the main obstacles do not stem from the questionable suitability of membrane filters but from the toxicity of the Endo-agar. The use of lactose-pepton (L.P.)-broth (German Standard Methods 1971) equally does not lead to satisfactory results if compared to the use of casein-soya (C.S.)-broth.