Isolation of Yersinia enterocolitica from Pig Tonsils.

Yersinia enterocolitica serotype 0:5 was isolated from the tonsils of 8 of 27 butcher hogs subjected to normal slaughtering procedures. Isolation through enrichment in cold mannitol broth or a bile medium at 4 C for 10-60 days was equally effective. Enrichment in modified Rappaport broth at 25 C for longer than 2 days sharply decreased recovery of Y. enterocolitica from tonsils. The type of enrichment medium also had a marked effect on the recovery efficiency of different strains of Y. enterocolitica from ground meat.