Listeria monocytogenes Contamination in Pork Can Originate from Farms

Abstract

The presence of Listeria monocytogenes in the pork production chain was followed from farm to slaughterhouse by examining the farm and slaughterhouse levels in the same 364 pigs, and finally by analyzing the cut meats from the same pig lots. Both organic and conventional farms were included in the study. Altogether, 1,962 samples were collected, and the 424 L. monocytogenes isolates were analyzed by pulsed-field gel electrophoresis. The results from microbial analyses were combined with data from an on-farm observation and a questionnaire to clarify the associations between farm factors and prevalence of L. monocytogenes. The prevalence of L. monocytogenes was 11, 1, 1, 24, 5, 1, and 4% in feed and litter, rectal swabs, intestinal contents, tonsils, pluck sets (including lungs, heart, liver, and kidney), carcasses, and meat cuts, respectively. The prevalence was significantly higher in organic than in conventional pig production at the farm and slaughterhouse level, but not in meat cuts. Similar L. monocytogenes genotypes were recovered in different steps of the production chain in pigs originating from the same farm. Specific farm management factors, i.e., large group size, contact with pet and pest animals, manure treatment, use of coarse feed, access to outdoor area, hygiene practices, and drinking from the trough, influenced the presence of L. monocytogenes in pigs. L. monocytogenes was present in the production chain, and transmission of the pathogen was possible throughout the chain, from the farm to pork. Good farm-level practices can therefore be utilized to reduce the prevalence of this pathogen.

Listeria monocytogenes prevalence, contamination levels and strains characterization throughout the Parma ham processing chain

“…Recent findings of genetic homogeneity between strains isolated in farms and in fresh pork meat (Hellströ et al, 2010) suggest that primary production may represent a potential source of L. monocytogenes contamination in pork meat processing industry. On the contrary, the European Food Safety Authority has claimed the marginality of transfers of L. monocytogenes from primary production to processed products (European Food Safety Authority, 2008).…”

“…Asymptomatic pigs are known to serve as vehicle of L. monocytogenes and to be one source of contamination in pork meat (Beloeil et al, 2003;Giovannacci et al, 1999;Hellströ et al, 2010). Nevertheless, several studies support the finding that the contamination of RTE food may originate from the colonization of L. monocytogenes during late processing stages (European Food Safety Authority, 2008;Tompkin, 2002).…”

Prevalence of Listeria monocytogenes in pork-meat and other processed products from the Colombian swine industry

“…For example it has been shown that pork lodge this bacterium in tonsils and intestine (3,21,22,28). For this reason if during evisceration there is organ rupture, the carcass can be contaminated with L. monocytogenes.…”

“…Although it is frequent for L. monocytogenes to contaminate carcasses and processing plants, subsequent washing and disinfecting procedures should get rid of the contamination. Pathogen-free product depends on the effectiveness of these processes (21).…”

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

“…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. Rutjes et al (2014) found that the pig seroprevalence of Hepatitis E virus to be significantly higher (p<0.05) in organic pigs.…”