Split Marketing as a Risk Factor for Salmonella enterica Infection in Swine

Livestock Behavior Research Unit, Agricultural Research Service, U.S. Department of Agriculture, West Lafayette, Indiana 47907, USA.
Foodborne Pathogens and Disease (Impact Factor: 1.91). 09/2009; 6(7):865-9. DOI: 10.1089/fpd.2009.0309
Source: PubMed


On-farm reduction of Salmonella carriage prevalence in pigs requires the identification of risk factors to direct interventions development. This study was designed to determine if split marketing of finishing pigs constitutes a risk factor for Salmonella infections, by comparing Salmonella prevalence in the first group of pigs selected for harvest ("first pull") versus the prevalence in the last group of pigs selected for harvest ("close out") from multiple commercial finishing lots. Nine paired samplings were conducted consisting in matched groups of pigs from individual barns as the first pull and the close out with a 4-week interval between groups. From each group, fecal and meat samples were collected, on-farm and at harvest, respectively. Fecal samples were selectively enriched, and analyzed for the presence of Salmonella, whereas meat juice samples were analyzed for the presence of antibodies against Salmonella. In 7/9 (77.8%) of the studied barns, an increase in Salmonella prevalence was observed, based on both bacteriologic and serologic analysis. Overall, there was an increase of 9.2% (p < 0.05) in bacteriologic prevalence, and 31.3% (p < 0.05) in serologic prevalence from first pull to close out groups. This study demonstrates that a significant increase in Salmonella prevalence occurs between the first and the last group of pigs harvested from finishing lots, with close out groups of market pigs posing a higher risk for Salmonella contaminations.

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    • "Recently, the use of molecular tests was used to assess the presence of Salmonella in ICLN and the results indicate that the concentration of Salmonella was very low and bacterial cells were mostly unevenly distributed within the tissue (Mann et al., 2014). It should also be pointed out that stress factors associated with transport have been linked to increased pathogen carriage, disease susceptibility, carcass contamination and pathogen shedding (Burkholder et al., 2008; Rostagno et al., 2009). Detection of Salmonella in the cecal content may be due to either active infection or transit through gut, whereas the presence in lymph nodes suggests infection that unlikely occurred between the farm and slaughter. "
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    ABSTRACT: The key component of most European pig Salmonella control programmes is the classification of herds according to seroprevalence at slaughter. The objectives of this study were to estimate the true Salmonella seroprevalence, and investigate the association between the true status of infection and serology in slaughter heavy pigs. Blood of 3340 pigs was collected and tested with ELISA. From 385 pigs, also lymph nodes and cecal content were collected for bacteriology. Analysis was performed in a Bayesian framework. Results showed that a large proportion of pigs was serologically positive (herd seroprevalence 93% and within-herd seroprevalence higher than 81% in half of herds at cut-off 10 OD%). The association between the true status of infection and serology was not significant, and therefore the classification of heavy pig herds according to seroprevalence at slaughter would not be suitable to reduce the risk of introducing Salmonella into the food chain. Copyright © 2015 Elsevier Ltd. All rights reserved.
    Research in Veterinary Science 07/2015; 101. DOI:10.1016/j.rvsc.2015.06.015 · 1.41 Impact Factor
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    • "2011) and in experimentally infected and slaughtered swine (Wingstrand et al., 1997; Lundén et al., 2002). Meat juice is also used for the detection of other foodborne pathogens, such as Trichinella, Ostertagia ostertagi, Fasciola haepatica, Taenia saginata , Salmonella, and Porcine reproductive and respiratory system virus (Beck et al., 2005; Abuseir et al., 2007; Charlier et al., 2009; Rostagno et al., 2009; Gó mez-Laguna et al., 2010). "
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    ABSTRACT: Serum and meat juice analyses for the detection of Toxoplasma gondii antibodies by an immunofluorescence antibody assay were compared in 100 seropositive and 100 seronegative slaughtered heavy swine. Meat juice was obtained from diaphragm and gracilis muscles of the serologically tested animals. Seventy-two diaphragmatic meat juice samples (36%, 95% interval confidence [IC] 29.4%-43.1%) and 63 gracilis meat juice samples (31.5%, 95% IC 25.1%-38.4%) tested positive for T. gondii antibodies. The average concordance between serum and meat juice derived from both muscles was "substantial" (K=0.6-0.8). The K-value was 1 when considering serum samples showing a titer >1/16, whereas it decreased to 0.62 and to 0.49 when considering serum samples with a 1/16 titer in meat juice from diaphragm and gracilis muscle, respectively.
    Foodborne Pathogens and Disease 01/2012; 9(1):75-8. DOI:10.1089/fpd.2011.0930 · 1.91 Impact Factor
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    • "It has been shown that when the heaviest pigs are removed first for market, the lighter pigs that remain in the barn present significantly higher levels of Salmonella prevalence in faeces, indicating some potential reactivation of the infection at that time and, therefore, an increased exposure to Salmonella for the non-infected pigs in the box. However, under this scenario, a serological response is detected at the slaughterhouse (Rostagno et al., 2009). In our farms, this practice is common and the time between both groups of pigs usually reaches up to 30 days, which would have allowed for the detection of an immune response if pigs were infected. "
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    ABSTRACT: The control of animal salmonellosis is considered as a major objective in Europe and indirect ELISAs will be important tools for the implementation of control programs for this infection in pigs. We analyse the results yielded by three commercial ELISAs (Herdcheck Swine Salmonella, SALMOTYPE Pig Screen, and PrioCHECK Salmonella) on meat juice samples from a population of slaughter pigs of Aragon, NW Spain, to assess their efficacy using traditional and latent-class approaches. Overall, the Herdcheck Swine Salmonella detected more Salmonella-infected pigs than the other two tests, but its relative sensitivity was low (65.9%). A similar result was observed when only serotypes detectable by this test were considered (69.1%). When a Bayesian approach was used the Herdcheck Swine Salmonella showed also the highest overall accuracy (sensitivity = 88% and specificity = 74%). Our results suggest that a relatively small proportion of the observed prevalence in herds would be explained by using these ELISAs. Also, this study points out that when different ELISA tests are used within the same herd, results may differ substantially. Thus, caution is advised if it is decided to use these assays for herd health classification in Spanish Salmonella control programs.
    Zoonoses and Public Health 11/2010; 57 Suppl 1(s1):107-14. DOI:10.1111/j.1863-2378.2010.01364.x · 2.37 Impact Factor
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