[Improved method for isolating Yersinia enterocolitica]

Investigations were carried out to restore and isolate Yersinia enterocolitica from both pure and mixed cultures as well as from sewage waters through enriching and alkaline treatment, employing the method of Aulisio and coll. It was found that the peptone used for the purpose (containing sorbitol, 10.0, yeast extract, 5.0, sodium taurocholate, 2.0, bacto-peptone, 2.0, bacto-tryptone, 2.0, bromthymol blue, 0.007, and 1/15 phosphate buffer, 1000 cm3 at pH = 7) made it possible for Y. enterocolitica to replicate at 4 degrees C in 8 to 10 days and inhibited the development of many other organisms. Enriching the medium at 4 degrees C with the alkaline treatment that followed enabled the isolation of Y. enterocolitica from mixed cultures and sewage waters from milk-processing enterprises in a very high percent of the cases as against enriching at 22 degrees C. Such enriching broth could be used not only for the enriching of Y. enterocolitica at 4 degrees C, but also for the differentiation of pure cultures in culturing at the same temperature.