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ARS Home » Midwest Area » Ames, Iowa » National Animal Disease Center » Food Safety and Enteric Pathogens Research » Research » Publications at this Location » Publication #126610
Title: SALMONELLA ENTERICA INFECTIONS IN MARKET SWINE WITH AND WITHOUT TRANSPORT AND HOLDING

Author
item HURD, HOWARD
item MCKEAN, J - IOWA STATE UNIVERSITY
item GRIFFITH, R - IOWA STATE UNIVERSITY
item WESLEY, IRENE
item ROSTAGNO, M - VISITING SCIENTIST BRAZIL

Submitted to: Applied and Environmental Microbiology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/2/2002
Publication Date: N/A
Citation: N/A

Interpretive Summary: This study suggests that rapid infection during transport and particularly during holding is a major reason for increased Salmonella prevalence before slaughter. This finding identifies an important control point in the pork production chain. The objective of this study was to compare, using identical sample types, the Salmonella enterica prevalence among pigs necropsied on-farm and those necropsied at the abattoir, after transport and holding. From six herds, we necropsied 567 market weight pigs (> 70 kg). Pigs were alternately assigned to be necropsied on-farm or at the abattoir. One-half of the group was sent, in clean disinfected trailers, to slaughter at a commercial abattoir. After transport (mean = 169 km) and 2-3 hours holding in antemortem pens, these pigs were necropsied. The 50 pigs remaining on the farm were necropsied the following day. The same samples were collected for Salmonella culture at both locations. Results show a 7-fold higher (P < 0.001) Salmonella isolation rate from pigs necropsied at the abattoir (39.9%; 114/286) compared to those necropsied on the farm (5.3%; 15/281). This difference was also observed for each individual herd. Recovery of additional serovars at the abattoir suggests the pigs are receiving S. enterica from extra-farm sources. This information will benefit scientists, packing plants, producers, practitioners, the Animal and Plant Health Inspection Service, and the Food Safety and Inspection Service.

Technical Abstract: The objective of this study was to compare, using identical sample types, the Salmonella enterica prevalence among pigs necropsied on- farm and those necropsied at the abattoir, after transport and holding. From six herds, we necropsied 567 market weight pigs (> 70 kg). Pigs were alternately assigned to be necropsied on-farm or at the abattoir. One half of the group was sent, in clean disinfected trailers, to slaughter at a commercial abattoir. After transport (mean = 169 km) and 2-3 hours holding in antemortem pens, these pigs were necropsied. The 50 pigs remaining on the farm were necropsied the following day. The same samples types were collected for S. enterica culture at both locations. Results show a 7-fold higher (P < 0.001) S. enterica isolation rate from pigs necropsied at the abattoir (39.9%; 114/286) compared to those necropsied on the farm (5.3%; 15/281). This difference was also observed for each individual herd. All sample types showed a significantly higher prevalence when comparing abattoir to on-farm collection, respectively: lymph nodes (9.15% vs. 3.6%), cecal contents 13.6% vs. 1.8%, 1 g fecal 25.2% vs. 0.7%. Recovery of additional serovars at the abattoir suggests the pigs are receiving S. enterica from extra- farm sources. This study suggests that rapid infection during transport and particularly during holding is a major reason for increased S. enterica prevalence, preharvest. This finding identifies an important S. enterica control point in the pork production chain.