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Bessire BC, Thomas M, Gehring KB, Savell JW, Griffin DB, Taylor TM, Mikel WB, Campbell JA, Arnold AN, Scaria J. National survey of Salmonella prevalence in lymph nodes of sows and market hogs. Transl Anim Sci 2018; 2:365-371. [PMID: 32704719 PMCID: PMC7200438 DOI: 10.1093/tas/txy072] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2018] [Accepted: 06/12/2018] [Indexed: 11/28/2022] Open
Abstract
Livestock are known to harbor Salmonella in their gastrointestinal (GI) tract and lymphatic tissues. Pathogens may be transferred from the GI tract to external carcass surfaces during normal harvest procedures but can be mitigated by antimicrobial carcass interventions. Lymph nodes (LNs) are typically encased in fat and are protected from antimicrobial carcass surface treatments, thus serving as a possible root cause of foodborne illnesses attributed to Salmonella in meat products. Members of the pork industry are committed to food safety and want to better understand Salmonella as a potential contaminant in pork products. To establish a baseline of Salmonella prevalence in porcine LNs across the United States, 21 commercial pork harvest facilities, representing northern (n = 12) or southern (n = 9) geographical regions, participated in this study. As processing volumes allowed, 25 carcasses were selected from each establishment. From each carcass, left and right superficial inguinal LNs (n =1,014 LNs) were removed and pooled to yield one sample per animal or n = 507 total LN samples. Salmonella prevalence rates differed (P < 0.05) between hog types in both regions. Specifically, 6.4% of market hog and 37.0% of sow samples were Salmonella positive in the northern region. This was reversed in the southern region as 13.0% of market hog and 4.8% of sow samples were Salmonella positive. There also was a difference (P < 0.05) in prevalence rates between northern and southern regions for sows, but not market hogs (P > 0.05). Type of chilling method (conventional, blast, or other) used at each market hog facility (n = 12) was documented. In the northern region, prevalence rates of Salmonella across chilling types were as follows: 20.0%, 2.7%, and 1.3% positive samples for conventional, other, and blast chill methods, respectively. In the southern region, 20.0% of samples were positive for conventional, 0.0% for blast, and 12.0% for other chilling methods. In both regions, samples from conventionally chilled carcasses returned more (P < 0.05) positive results than any other chill method. Overall, the higher rate of Salmonella prevalence in northern sows warrants further investigation, and members of the pork industry would benefit from the identification of possible methods to address the presence of Salmonella in porcine LNs.
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Affiliation(s)
- Baylee C Bessire
- Department of Animal Science, Texas A&M AgriLife Research, Texas A&M University, College Station, TX
| | - Milton Thomas
- Department of Veterinary and Biomedical Sciences, South Dakota State University, Brookings, SD
| | - Kerri B Gehring
- Department of Animal Science, Texas A&M AgriLife Research, Texas A&M University, College Station, TX
| | - Jeffrey W Savell
- Department of Animal Science, Texas A&M AgriLife Research, Texas A&M University, College Station, TX
| | - Davey B Griffin
- Department of Animal Science, Texas A&M AgriLife Research, Texas A&M University, College Station, TX
| | - T Matthew Taylor
- Department of Animal Science, Texas A&M AgriLife Research, Texas A&M University, College Station, TX
| | | | | | - Ashley N Arnold
- Department of Animal Science, Texas A&M AgriLife Research, Texas A&M University, College Station, TX
- Corresponding author:
| | - Joy Scaria
- Department of Veterinary and Biomedical Sciences, South Dakota State University, Brookings, SD
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Abstract
Major structural changes in livestock production in developed countries, particularly intensive confinement production and increases in herd and flock sizes, have raised several societal concerns about the future directions and implications of livestock food production, including the safety of meat products. This review of the major parasitic and bacterial foodborne pathogens associated with pork production indicates that pork safety in the United States has improved demonstrably over recent decades. Most notably, changes in swine production methods have been associated with virtual elimination of risk of the foodborne parasites Taenia solium, Trichinella spiralis, and Toxoplasma gondii from pigs reared on modern intensive farms. This represents a substantial public health achievement that has gone largely unheralded. Regulatory changes have led to demonstrably lower prevalence of Salmonella on pork carcasses, but control of bacterial foodborne pathogens on farms remains a significant challenge. Available evidence does not support the hypothesis that intensive pork production has increased risk for the major bacterial foodborne pathogens that are common commensals of the pig (Salmonella, Campylobacter, Listeria, and Yersinia enterocolitica), or that pigs produced in alternative systems are at reduced risk of colonization with these organisms. However, pigs raised in outdoor systems inherently confront higher risks of exposure to foodborne parasites, particularly T. gondii.
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Affiliation(s)
- Peter R Davies
- Department of Veterinary Population Medicine, College of Veterinary Medicine, University of Minnesota, St. Paul, MN 55108, USA.
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Wang B, Wesley IV, McKean JD, O'Connor AM. Sub-Iliac Lymph Nodes at Slaughter Lack Ability to PredictSalmonella entericaPrevalence for Swine Farms. Foodborne Pathog Dis 2010; 7:795-800. [DOI: 10.1089/fpd.2009.0459] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Affiliation(s)
- Bing Wang
- Department of Veterinary Diagnostic and Production Animal Medicine, College of Veterinary Medicine, Iowa State University, Ames, Iowa
| | - Irene V. Wesley
- Pre-Harvest Food Safety and Enteric Diseases Research Unit, National Animal Disease Center, Agricultural Research Service, U.S. Department of Agriculture, Ames, Iowa
| | - James D. McKean
- Department of Veterinary Diagnostic and Production Animal Medicine, College of Veterinary Medicine, Iowa State University, Ames, Iowa
| | - Annette M. O'Connor
- Department of Veterinary Diagnostic and Production Animal Medicine, College of Veterinary Medicine, Iowa State University, Ames, Iowa
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