Low Prevalence of Listeria monocytogenes in Cull Sows and Pork

Abstract

The goal of this study was to determine the prevalence of Listeria monocytogenes in sows slaughtered at a single Midwestern plant on two occasions (trial 1, n = 179 sows; trial 2, n = 160 sows). Fecal samples collected antemortem (trial 1) as well as animal tissues, and carcass swabs collected at the abattoir (trials 1 and 2) were analyzed. Eight isolates of L. monocytogenes were recovered from five samples that represented 0.18% of the total samples (n = 2,775). In trial 1, L. monocytogenes was detected in a tonsil sample (0.6%; 1 positive of 181 tonsils), in a carcass (0.6%; 1 positive of 179 carcasses), which was sampled prior to the organic rinse, and in two chopped meat block samples (1.2%; 2 positive of 165 samples). In trial 2, L. monocytogenes was only detected in a single chopped meat block sample (0.15%; 1 positive of 688 total samples). These data indicate the low prevalence of L. monocytogenes in the cull sow.

Analysis of Listeria monocytogenes Strain Distribution in a Pork Slaughter and Cutting Plant in the Province of Quebec

“…In our study, the strains of serogroup IVb presented a 3-amino-acid deletion in the inlA sequence that has been linked with highly invasive strains (33). The presence of strains of this serogroup in the feces of live pigs has already been described, supporting the evidence that live pigs may introduce these strains into meat processing plants (7,53). Despite the low contamination level found in lairage pens, a variety of pulsotypes was found.…”

“…The strain associated with this outbreak was of serovar l/2a (serogroup Ila). This serovar was also linked to a cheese-associated outbreak that occurred in the same year animals (5,30,53). L. monocytogenes has been found in the feces, intestines, and tonsils of healthy pigs on farms at levels ranging from 0 to 61% (16,30,47,53).…”

“…This serovar was also linked to a cheese-associated outbreak that occurred in the same year animals (5,30,53). L. monocytogenes has been found in the feces, intestines, and tonsils of healthy pigs on farms at levels ranging from 0 to 61% (16,30,47,53). Contaminated pigs could therefore be responsible for the contamination of the environment in lairage pens or during the slaughtering and processing operations (4,25).…”

“…Contaminated pigs could therefore be responsible for the contamination of the environment in lairage pens or during the slaughtering and processing operations (4,25). Differences in husbandry practices, such as the use of wet feeding, which is common in Europe, as well as the use of various isolation protocols, could possibly be responsible for the differences in prevalence in the studies (5,7,53). Some authors have suggested that L. monocytogenes contamination levels upon plant entry are amplified in the chilling and cutting zone (47).…”

Incidence and antimicrobial susceptibility of Salmonella, Listeria, and Campylobacter spp. in raw “souvlaki” marketed in Thessaloniki (Northern Greece)

“…In addition, the organism is able to adhere and persist for long periods on the surface of equipment forming biofilms (Kornacki and Gurtler, 2007). L. monocytogenes can be found at all stages of pork meat industry with increasing prevalence from the slaughterhouse to the cutting room (Thénevot et al, 2006a;López et al, 2008;Wesley et al, 2008). Our results could confirm our previous study carried out on raw minced pork which showed that 35.0% and 8.0% of the samples examined proved positive for Listeria spp.…”