Submitted to: International Symposium on the Epidemiology and Control of Foodborne Pathogens in Pork
Publication Type: Abstract only
Publication Acceptance Date: 8/25/2009
Publication Date: 9/30/2009
Citation: Rostagno, M.H., Eicher, S.D., Lay Jr, D.C. 2009. Effect of Feed Withdrawal and Transportation on Salmonella Enterica Infection in Market-weight Pigs. International Symposium on the Epidemiology and Control of Foodborne Pathogens in Pork. Proceedings. Interpretive Summary:
Technical Abstract: Market pigs infected with Salmonella pose a significant food safety risk by carrying the pathogen into abattoirs. Pre-slaughter stress is believed to cause increased levels of Salmonella in infected pigs, therefore increasing food safety risk. A study was conducted to determine if two common pre-slaughter stressors, feed withdrawal and transportation, affect the levels of Salmonella in infected market pigs. A total of 60 market-weight pigs (220 – 240 lbs.) were individually inoculated (intranasally; 105 cfu/mL) with Salmonella enterica serovar Typhimurium. The experiment was replicated 3 times with 20 pigs per replicate. Individual fecal samples were collected to confirm establishment of the infection (3 samples per pig) prior to treatment assignment. Three days post-challenge, pigs were randomly assigned to 4 treatments (5 pigs per treatment), including; 1) control or no stress, 2) feed withdrawal for 12 hours, 3) transportation for 2 hours, and 4) feed withdrawal for 12 hours and transportation for 2 hours. Following treatments, pigs were subjected to euthanasia and necropsy for collection of ileal, cecal and rectal contents, and mesenteric lymph nodes. All samples were processed for the isolation and enumeration of Salmonella. No difference between treatments was found on the frequency of Salmonella-positive samples. Feed withdrawal by itself or followed by transportation caused a significant increase in Salmonella concentration in ileal contents (P<0.05). Only an interaction between feed withdrawal and transportation caused a numerical increase of Salmonella concentration in cecal contents. Rectal contents (i.e., feces) consistently contained very low concentrations of Salmonella regardless of the treatment. This study reveals which elements of typical pre-slaughter practices lead to greater intestinal Salmonella concentrations in market pigs.