Relevance of Meat Juice Seroprevalence and Presence of Yersinia enterocolitica and Salmonella spp. in Pig Tonsils for Risk Management at Slaughter

Salmonella spp. and Yersinia enterocolitica are priority bacteriological public health hazards in pork safety. For more successful control, it is necessary to collect data on their prevalence throughout the meat chain using the concept of harmonized epidemiological indicators. The aim of this study was to determine their prevalence in fattening pigs under different housing conditions by recovering the pathogen from tonsils and by serological testing of diaphragm meat juice at slaughterhouses. The overall prevalence of Salmonella spp. and Y. enterocolitica in tonsils was 9.8% and 6.5%, respectively, with no significant differences between large and small farms (p > 0.05). In general, seroprevalence of Salmonella spp. was 48.35% and of Yersinia 13.18% (p < 0.05) but without significant differences of individual seroprevalence between farm types. No association was found between detection of Salmonella spp. or Y. enterocolitica in tonsils and seroprevalence (fc = 0.121, p = 0.420; fc = 0.027, p = 0.718, respectively). Significantly higher seroprevalence of Salmonella spp. was found on farms with lower biosecurity status (p < 0.05). A higher recovery rate of Salmonella spp. and Y. enterocolitica from the tonsils may be expected in seropositive pigs (OR 1.56-2.36), but without statistical significance. The results showed that Salmonella and Yersinia meat juice serology can be considered for risk categorization of pig farms as a less-time consuming and more sensitive method compared to microbiological testing of tonsils but must be combined with analyses of other risk factors relevant to infection or contamination in the pork chain.