Transmission of Yersinia pseudotuberculosis in the Pork Production Chain from Farm to Slaughterhouse

Abstract

The transmission of Yersinia pseudotuberculosis in the pork production chain was followed from farm to slaughterhouse by studying the same 364 pigs from different production systems at farm and slaughterhouse levels. In all, 1,785 samples were collected, and the isolated Y. pseudotuberculosis strains were analyzed by pulsed-field gel electrophoresis. The results of microbial sampling were combined with data from an on-farm observation and questionnaire study to elucidate the associations between farm factors and the prevalence of Y. pseudotuberculosis. Following the same pigs in the production chain from farm to slaughterhouse, we were able to show similar Y. pseudotuberculosis genotypes in live animals, pluck sets (containing tongue, tonsils, esophagus, trachea, heart, lungs, diaphragm, liver, and kidneys), and carcasses and to conclude that Y. pseudotuberculosis contamination originates from the farms, is transported to slaughterhouses with pigs, and transfers to pluck sets and carcasses in the slaughter process. The study also showed that the high prevalence of Y. pseudotuberculosis in live pigs predisposes carcasses and pluck sets to contamination. When production types and capacities were compared, the prevalence of Y. pseudotuberculosis was higher in organic production than in conventional production and on conventional farms with high rather than low production capacity. We were also able to associate specific farm factors with the prevalence of Y. pseudotuberculosis by using a questionnaire and on-farm observations. On farms, contact with pest animals and the outside environment and a rise in the number of pigs on the farm appear to increase the prevalence of Y. pseudotuberculosis.

Wild Boars as an Important Reservoir for Foodborne Pathogens

“…In Switzerland, Y. enterocolitica was detected in 88% of the tonsils of slaughtering pigs using PCR (Fredriksson-Ahomaa et al, 2007), whereas there are no data available on the occurrence of Y. pseudotuberculosis in these animals from Switzerland. The high detection rate of Y. pseudotuberculosis in wild boars in this study might be due to the close contact with other wild animals as was shown by Laukkanen et al (2008) for organically held fattening pigs. Besides herd size and herd management, mixing of batches appears to be a major risk factor for the increase of prevalence of Y. enterocolitica in fattening pigs (Fosse et al, 2009).…”

Relation Between Serology of Meat Juice and Bacteriology of Tonsils and Feces for the Detection of EnteropathogenicYersiniaspp. in Pigs at Slaughter

“…During slaughter and dressing operations, enteropathogenic Yersinia spp. may spread to the rest of the carcass (Borch et al, 1996;Laukkanen et al, 2008Laukkanen et al, , 2009.…”

“…As carcass contamination with enteropathogenic Yersinia spp. depends on the contamination status of pigs delivered to the slaughterhouse (Laukkanen et al, 2008(Laukkanen et al, , 2009), incoming pig batches should be differentiated with respect to the risk they pose for public health (EFSA, 2011). Bacteriological monitoring of tonsils provides the best indication for the presence of Yersinia in slaughter pigs (Nesbakken et al, 2006), albeit time consuming and labor intensive (Fredriksson-Ahomaa and Korkeala, 2003).…”

Sustainability of livestock production systems : a comparing conventional and organic livestock husbandry

“…Generalising the results from these papers to the entire organic and conventional sectors is therefore complicated. Laukkanen et al (2008) found the Yersinia pseudotuberculosis prevalence in pigs to be significantly higher (p<0.05) in organic farming, but did not mentioned the significance levels of the differences in sample, intestinal tract, tonsil, pluck set and carcass prevalence. Hellstrom et al (2010) found the pig, intestinal tract, tonsil, pluck set (heart, lungs, oesophagus, trachea, diaphragm, liver, kidneys, and tongue with tonsils) and carcass prevalence of L. monocytogenes to be significantly higher (p<0.05) in organic pigs.…”