Submitted to: Journal of Animal Science
Publication Type: Abstract only
Publication Acceptance Date: 3/2/2011
Publication Date: 7/10/2011
Citation: Rostagno, M.H., Eicher, S.D., Lay Jr, D.C. 2011. Does pre-slaughter stress affect pork safety risk?. Journal of Animal Science. 89 (E-Suppl. 1):430. Interpretive Summary:
Technical Abstract: Salmonella is the top food safety priority for the pork industry. Although contamination of pork occurs along the slaughter and processing line, infected live pigs entering the abattoir constitute the original Salmonella contamination source. However, the extent of carcass contamination is not only determined by the number of pigs infected, but also by the levels of Salmonella entering the abattoir in the intestinal tract of slaughtered pigs. Therefore, a series of experiments was conducted to determine if common stressors occurring prior to slaughter affect the prevalence and levels of Salmonella in market pigs. Initially, a field study was conducted to determine the effect of transportation and lairage on the frequency of Salmonella shedding in market pigs. A follow up study was conducted under controlled conditions to determine the effect of feed withdrawal and transportation on the levels of Salmonella in the intestinal tract of infected market-weight pigs. Finally, a third study was conducted to determine the effect of transportation and mixing with unfamiliar pigs on the susceptibility of market-weight pigs to Salmonella infection. In the first study, Salmonella shedding increased (P<0.05) from pre-transport (11.3%) to post-transport (20%), and from post-transport to post-lairage (42%). In the second study, feed withdrawal by itself or combined with transportation caused increased levels of Salmonella in the ileum (P<0.05), whereas only the combination of feed withdrawal and transportation caused increased levels of Salmonella in the cecum (P<0.05). In the third study, pigs subjected to transportation and/or mixing were colonized by higher (P<0.05) levels of Salmonella in the ileum, whereas only pigs subjected to both stressors combined were colonized by higher (P<0.05) Salmonella levels in the cecum. It is concluded that pre-slaughter stressors, such as transportation, feed withdrawal and mixing, affect pork safety risk by increasing frequency and levels of Salmonella in the intestinal tract of market-weight pigs.