Submitted to: Research Workers in Animal Diseases Conference Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: 11/13/2001
Publication Date: N/A
Citation: Interpretive Summary:
Technical Abstract: Market pigs (penmates) were randomly assigned to be necropsied on the farm of origin or at the abattoir, after transport in disinfected trailers, and 2-3 hours holding. The same samples (feces, ileocecal lymph node, cecal content, superficial inguinal lymph node) were collected at both locations. For five of the six farms in this study, the isolation rates were significantly higher for penmates after transport and holding. Overall the average Salmonella isolation rate was five times higher for pigs necropsied after transport and short-term holding. After this study, we conducted an experimental study. The objective was to evaluate the possibility of swine becoming infected with Salmonella typhimurium, in a 2-3 hour interval, from an environment contaminated with Salmonella. Forty crossbred market weight swine (~92 kg) were exposed to marked strain of Salmonella typhimurium in simulated holding conditions. The contaminated feces were deposited on the floor by swine that had been intranasally inoculated 4 days previously. Exposed pigs were autopsied at 2, 3, and 6 hours after exposure to the contaminated floor. Within 2 to 3 hours, most of exposed animals were positive for the marked Salmonella typhimurium strain. After 6 hours, all of the animals had at least one tissue sample test positive. These studies demonstrate that market swine can become infected with Salmonella in the short waiting time before slaughter. In combination, they suggest that intervention at the holding pen may have a significant impact on the safety of pork products.