Prevalence of Salmonella serotypes on pig carcasses from high- and low-risk herds slaughtered in three abattoirs

Quirke, Anne Marie; Leonard, Nola; Kelly, Gabrielle; Egan, John; Lynch, P. B.; Rowe, Theresa; Quinn, Patrick

doi:10.31274/safepork-180809-1128

Cited by 19 publications

(25 citation statements)

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“…A significant correlation between herd seroprevalence and bacteriological findings in the caecal contents was described in United Kingdom [10]. Quirke et al [27] also showed that, for a pig, belonging to a herd with more than 32% of seropositive animals was a significant risk factor for Salmonella caecal contamination at the slaughterhouse.…”

Section: Discussionmentioning

confidence: 94%

Impact of the Salmonella status of market-age pigs and the pre-slaughter process on Salmonella caecal contamination at slaughter

et al. 2004

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-The aim of this study was to evaluate the impact of the pre-slaughter process on Salmonella caecal contamination of pigs at slaughter. An observational study was carried out in 2001 on 101 conventional farrow-to-finish pig farms. On each farm, one batch of contemporary pigs was followed from the end of the fattening period until slaughter. The Salmonella bacteriological status of the batches was assessed by environmental samples of faecal material. The serological Salmonella status was obtained on 30 individually identified market-age pigs using an indirect ELISA test. At the slaughterhouse, 25 g of caecal contents were taken from 10 of the identified pigs. Faecal and caecal material were analysed according to a classical bacteriological method. A questionnaire was designed to obtain information about the type of feeding during the fattening period (dry versus wet), the duration of fasting on the farm before leaving for the slaughterhouse, the duration of transport between the farm and the slaughterhouse, the holding time in lairage at the slaughterhouse and loading and unloading conditions on the farm and at the slaughterhouse. To assess the relationships between these factors and the Salmonella caecal status of the pigs and the batches, two logistic models were fitted at the individual and at the batch level, respectively. The first analysis was performed using a random effects logistic regression model. The second analysis was based on a cumulative logit model with a positive caecal rate classified into three classes as the outcome variable. The results showed that the Salmonella status of market-age pigs assessed on the farm either by serological or bacteriological examinations and the time spent in lairage before slaughtering played a crucial role on caecal contamination. In the light of these results, actions should be considered both on the farm and at the slaughterhouse to decrease the risk of Salmonella contamination of the caecal contents.

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Section: Discussionmentioning

confidence: 94%

Impact of the Salmonella status of market-age pigs and the pre-slaughter process on Salmonella caecal contamination at slaughter

et al. 2004

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“…and specific geographical areas reported a much higher incidence of Salmonella in their swine populations. Since then, many additional studies have focused on establishing the incidence of Salmonella in swine on the farm and at slaughter (8,9,11,20,22), as well as on investigating possible links between various preslaughter stresses and increased fecal shedding of Salmonella by swine (5,13,14,17). A natural extension of this research is to investigate the manner in which (9) A (2) a A total of 100 pigs were sampled at the postexsanguination step of processing and numbered sequentially.…”

Section: Discussionmentioning

confidence: 99%

Use of Pulsed-Field Gel Electrophoresis To Characterize the Heterogeneity and Clonality ofSalmonellaIsolates Obtained from the Carcasses and Feces of Swine at Slaughter

Wonderling

Pearce

Wallace

et al. 2003

Appl Environ Microbiol

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Salmonella enterica isolates were recovered from swine at a collaborating processing plant over a 2-month period in the spring of 2000. In the present study, molecular subtyping by pulsed-field gel electrophoresis (PFGE) was performed on the 581 confirmed Salmonella isolates from the 84 Salmonella-positive samples obtained from the previous study. A total of 32 different PFGE pulsotypes were observed visually, and a BioNumerics software analysis clustered those pulsotypes into 12 PFGE groups. The B, F, and G groups predominated throughout the sampling period and were isolated from 39, 22, and 13% of the swine, respectively. In addition, multiple isolates were obtained from 67 of the 84 Salmonella-positive samples, and subtyping revealed multiple PFGE profiles in 35 of these 67 (62%) samples. Both carcass and fecal isolates of Salmonella were recovered from 13 swine, resulting in "matched" samples. Molecular typing of the 252 isolates recovered from the matched samples revealed that 7 (54%) of the 13 carcasses were contaminated with Salmonella pulsotypes that were not isolated from the feces of the same animal. Conversely, from 6 of the 13 (46%) matched animals, Salmonella clonal types were isolated from the feces that were not isolated from the carcass of the same animal. These data establish that each lot of swine introduces new contaminants into the plant environment and that swine feces from one animal can contaminate many carcasses. In addition, these results indicate that the examination of multiple Salmonella isolates from positive samples is necessary to determine the variety of potential contaminants of swine carcasses during slaughter and processing.

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“…In Denmark [17], Germany [23] and Ireland [25], national control programmes, based on serological testing, are implemented in the pork production chain. Therefore, meat juice samples from a representative number of pigs per herd are collected at the slaughterhouse.…”

Section: Introductionmentioning

confidence: 99%

“…Such tests are, as generally accepted, a useful tool to determine the prevalence at the herd level [18,19] and to point out high-prevalence herds [17]. Depending on the prevalence as determined in these tests, herds are classified into different categories [17,23,25].…”

Section: Introductionmentioning

confidence: 99%

“…being present in the intestines or the associated lymph nodes that is important with regards to contamination of the carcasses [5]. In many studies, the association between serological and bacteriological results as measured in faecal samples has been calculated at the herd level [9,11,16,25,28,33] and at the individual level 1 [10,28]. The authors agree that the serological test is suitable for screening on a herd basis in control programmes aiming to reduce Salmonella prevalence in pork.…”

Section: Introductionmentioning

confidence: 99%

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Discrepancies between the isolation of Salmonella from mesenteric lymph nodes and the results of serological screening in slaughter pigs

et al. 2005

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-Most Salmonella control programmes are based on serological testing in the slaughterhouse. However, from a point of view of carcass contamination, it is rather the presence of Salmonella spp. in the animal at the time of slaughter that is important. The aim of this crosssectional study was to investigate the possible discrepancies between the isolation of Salmonella spp. in the mesenteric lymph nodes and the results of serological screening. In total, 1821 fattening pigs originating from 60 Belgian farrow-to-finish herds were sampled in the slaughterhouse. The serum samples were analysed using an indirect mix-ELISA for the presence of Salmonella antibodies and evaluated at 3 cut-off values namely 10, 20, and 40% Optical Density (OD). All mesenteric lymph node samples were submitted to qualitative Salmonella isolation and a representative number of isolates was serotyped. From each herd, 30 animals were screened both serologically and bacteriologically and the herd was considered as positive when at least one sample was positive. At the herd level, 83.6% (cut-off OD 40%) to 100.0% (cut-off OD 10%) of the herds from which Salmonella had been isolated were evaluated as seropositive. At the individual level, only 34.5% (cut-off OD 40%) to 82.8% (cut-off OD 10%) of the animals from which Salmonella had been isolated were seropositive. Overall, a weak agreement was found between bacteriology and serology for Salmonella diagnosis. If pig herds are categorised using serological tests in the slaughterhouse, one should be aware of the fact that slaughter pigs can still harbour Salmonella spp. in the mesenteric lymph nodes, without being detected in serological tests. The cut-off value used to evaluate a sample as serologically positive and the number of samples per herd are of major importance to classify herds correctly in order to protect human health.slaughter pig / Salmonella / bacteriology / serology * Corresponding author: nathalie.nollet@UGent.be Article published by EDP Sciences and available at

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Prevalence of Salmonella serotypes on pig carcasses from high- and low-risk herds slaughtered in three abattoirs

Cited by 19 publications

References 0 publications

Impact of the Salmonella status of market-age pigs and the pre-slaughter process on Salmonella caecal contamination at slaughter

Impact of the Salmonella status of market-age pigs and the pre-slaughter process on Salmonella caecal contamination at slaughter

Use of Pulsed-Field Gel Electrophoresis To Characterize the Heterogeneity and Clonality ofSalmonellaIsolates Obtained from the Carcasses and Feces of Swine at Slaughter

Discrepancies between the isolation of Salmonella from mesenteric lymph nodes and the results of serological screening in slaughter pigs

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