Enumeration of Yersinia enterocolitica O:3 from the porcine oral cavity, and its occurrence on cut surfaces of pig carcasses and the environment in a slaughterhouse.

The number of Yersinia enterocolitica serogroup O:3/biovar 4 recovered from five porcine tongues, ranged from 0-186/cm2, the corresponding range for the tonsils was, 0-1720/cm2. This bacterium was isolated from the oral cavity of 25 (83.3%) of 30 freshly eviscerated slaughter pigs. The isolation rates obtained from the different cut surfaces were: cranial incision, 46.7%; abdominal incision, 43.3%; and circumanal incision, 26.7%. Seven pigs harboured the bacteria in the oral cavity only, and one pig yielded Y. enterocolitica serogroup O:3/biovar 4 only from the abdominal incision. In eighteen pigs the bacteria was obtained from the oral cavity and at least one of the cut surfaces, four of these pigs yielding the bacteria from all sites sampled. Y. enterocolitica O:3/biovar 4 was isolated from samples taken from the following sites in the slaughterhouse: the floor in the bleeding area, the floor in the eviscerating area, the viscera table, and the floor next in line after the meat inspection area. The organism was not found on the floor in the meat inspection area. It is concluded that modern slaughtering technology and the routines followed by meat inspection personnel have probably contributed to the relatively high rates of this bacteria on carcass cut surfaces detected in this study. The results of this investigation thus emphasize the need to consider the introduction of changes in slaughtering technology and meat inspection practices presently being employed in Norwegian slaughterhouses.