#06-167

Complete

Date Full Report Received

07/23/2008

Date Abstract Report Received

07/23/2008

Investigation

Institution:
Primary Investigator:

Contamination of meat and meat products with foodborne pathogens is usually the result of the carcass coming in contact with the feces of an infected animal during processing. In the case of Salmonella, several recent studies have reported that pigs become rapidly infected with the organism during transport and lairage due to Salmonella contaminated trailers and holding pens. These infections serve to increase the likelihood of carcass contamination by amplifying the amount of bacteria that enters the processing facility. To counteract these infections, we have developed a phage based anti-Salmonella intervention strategy that can be administered to pigs just prior to transport and lairage. We have isolated and characterized 15 wild-type, Salmonella-specific phage and developed a means be which the viruses can be microencapsulated for administration to animals. Initial tests of the efficacy of our anti-Salmonella phage cocktail were conducted in small pigs (~20-30 pounds) where we treated the pigs with the phage cocktail and then inoculated them with Salmonella enterica Typhimurium. Infections in pigs administered the phage treatment were reduced 99.0% to 99.9% in the tonsils, ileum, and cecum. To test our anti-Salmonella phage cocktail in a more production-like setting, we infected (in three replicates) four market weight pigs with Salmonella enterica Typhimurium. These seeder pigs were allowed to contaminate a holding pen for 48 hours. At 48 hours post-inoculation, 16 naïve pigs (in three replicates) were introduced to the contaminated environment. Eight pigs were given the anti-Salmonella phage cocktail while the other eight were mock-treated. Phage treatment reduced cecal and ileal Salmonella infections by approximately 95% and 90%, respectively, in phage treated pigs. These data indicate that phage therapy can be used as an effective means to reduce or limit Salmonella infections during the crucial periods of transport and lairage. Contact person: Paul Ebner, Asst. Professor, Dept. of Animal Sciences, Purdue University, 915 W. State St., West Lafayette, IN 47907, 765-494-4820, pebner@purdue.edu.