SHORT-COMINGS OF IRGASAN TICARCILLIN CHLORATE BROTH FOR THE ENRICHMENT OF YERSINIA-ENTEROCOLITICA BIOTYPE-2, SEROTYPE-9 FROM MEAT

Recovery of Yersinia enterocolitica serotype 0:9 from artificially con taminated minced pork with the enrichment medium irgasan ticarcillin c hlorate broth (ITC) was poor. This was due to the lower growth rate of this serotype in comparison with serotype 0:3. Tests on the behaviour of serotype 0:3 and 0:9 towards some selective agents in ITC broth sh owed that the minimal inhibitory concentration of chlorate was much lo wer for serotype 0:9 than for serotype 0:3. Omitting chlorate in the I TC enrichment stimulated the growth of pure cultures. Reduction of MgC l2 and malachite green to 80% of the original concentration further in creased the growth, so that after 48 h of incubation similar counts (1 0(7)-10(8) cfu/ml) as for serotype 0:3 were obtained.