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United States Department of Agriculture

Agricultural Research Service

Title: Preslaughter Holding Environment in Pork Plants Is Highly Contaminated with Salmonella Enterica

Authors
item Rostagno, M - FEDERAL UNIV LAVRAS
item Hurd, Howard
item Mckean, J - IOWA STATE UNIVERSITY
item Ziemer, Cherie
item Gailey, Jared
item Leite, R - FED UNIV MINAS GERAIS

Submitted to: Applied and Environmental Microbiology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: May 27, 2003
Publication Date: August 20, 2003
Citation: ROSTAGNO, M.H., HURD, H.S., MCKEAN, J.D., ZIEMER, C.J., GAILEY, J.K., LEITE, R.C. PRESLAUGHTER HOLDING ENVIRONMENT IN PORK PLANTS IS HIGHLY CONTAMINATED WITH SALMONELLA ENTERICA. APPLIED AND ENVIRONMENTAL MICROBIOLOGY. 2003. V. 69. P. 4489-4494.

Interpretive Summary: The objective of this study was to determine if abattoir pens can provide a Salmonella enterica infection source during the 2 to 4 hours of pre-harvest holding. Pigs are routinely held for at least 2 hours to allow for antemortem inspection and improvements in meat quality. For 24 groups of pigs studied (~150 animals/group) in 2 high capacity abattoirs, fecal samples were collected from the transport trailer immediately after pigs were unloaded. Holding pens were sampled prior to entry of study pigs for the routine pre-slaughter holding period. After harvest, samples were collected from 30 pigs in each studied group. All samples were cultured for the isolation and serotyping of Salmonella enterica. Results show the study pens were highly contaminated with S. enterica; all holding pens sampled (100%) had at least one positive sample; 33% of waterers were positive. Many pigs had salmonella serovars that were only found in the pen samples collected before the study pigs entered. This study demonstrated holding pens could serve as an infection source immediately prior to harvest, and that abattoir holding pens are a hazard for Salmonella contamination in the pork production chain.

Technical Abstract: The objective of this study was to determine if abattoir pens can provide a Salmonella enterica infection source during the 2 to 4 h of pre-harvest holding. For 24 groups of pigs studied (~ 150 animals/group) in 2 high capacity abattoirs, 6 pooled fecal samples (n = 10 per pool) were collected from the transport trailer immediately after pigs were unloaded. Holding pens were sampled prior to entry of study pigs for the routine holding period (~ 2.5 h). Cecal contents and ileocecal lymph nodes were collected, on the processing line, from 30 pigs in each studied group. All samples were cultured for the isolation and identification of Salmonella enterica. The study pens were highly contaminated with S. enterica; all holding pens sampled had at least one positive sample. Additionally, 33% (8 of 24) of drinking water samples were positive. All 24 groups of pigs had S. enterica-positive cecal contents and ileocecal lymph nodes, including those groups from transport trailers with no positive samples. From pigs, trailers, and pens, 586 isolates representing 36 different Salmonella serovars were isolated. Of the 353 isolates isolated from the pigs (109 ileocecal lymph nodes plus 244 cecal contents), 19% were identified as the same serovar as those isolated from the respective pen; 27% were identified as the same serovar isolated from the trailer. Overall there were 151 unique, within group, serovars; 16% of the unique serovars matched between pigs and pens, suggesting that pen served as the infection source. This study demonstrated highly contaminated abattoir holding pens and watering sources. It also demonstrated holding pens could serve as an infection source. This study identifies the abattoir holding pens as a significant hazard and a potential control point for Salmonella contamination in the pork production chain.

Last Modified: 7/24/2014
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