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Title: Detection and isolation of Salmonella spp. in animal feeds from 2007-2011

item HSIEH, CHENG-YI - Texas A&M University
item LEE, KYUNG-MIN - Texas A&M University
item Poole, Toni
item RUNYON, MICK - Texas A&M University
item JONES, BEN - Texas A&M University
item HERRMAN, TIMOTHY - Texas A&M University

Submitted to: International Journal of Regulatory Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/10/2014
Publication Date: 12/20/2014
Citation: Hsieh, C., Lee, K., Poole, T.L., Runyon, M., Jones, B., Herrman, T.J. 2014. Detection and isolation of Salmonella spp. in animal feeds from 2007-2011. International Journal of Regulatory Science. 2:14-27.

Interpretive Summary: Bacteria that cause disease (pathogens) in humans and animals have caused a public health crisis because diseases once thought eradicated are reappearing. Many public health officials blame the food animal industry for the emergence of pathogenic bacteria and down-play the role of human medicine. Swine and cattle producers have long been under pressure to limit the presence of pathogenic bacteria that are often present on retail meat products. With the emergence of multi-drug resistant pathogens, there are new pressures to limit the use of antimicrobial agents. However, there is evidence that the reduction in antibiotic use alone is not sufficient to reduce antimicrobial-resistant bacterial populations. The limitation of antimicrobial use poses an additional dilemma for producers with regard to the maintenance of healthy herds as well as preventing the presence of pathogens on retail meat. There is an effort to determine the source of pathogens in food animal production. This study investigates the presence of Salmonella spp. in animal feed to determine if this is a possible source of contamination.

Technical Abstract: Salmonella species (spp.) are zoonotic pathogens that contaminate animal ingredients and finished feed and represent a significant hazard as identified by the Codex Animal Feed Taskforce. The U.S. Food and Drug Administration promulgated regulations prohibiting Salmonella contamination in feed and have since published a draft guidance document expressing their current strategy involving regulatory oversight of Salmonella contamination in feed. The Office of the Texas State Chemist initiated the broad surveillance of Salmonella spp. in 2007 in response to a Salmonella enterica serotype Typhimurium outbreak in frozen rodents, which are subject to the agency’s regulatory oversight as defined by the Texas Commercial Feed Control Act. From 2007-2011, 2622 total feed samples were collected and subsequently evaluated for Salmonella contamination using multiple first-line methods, the accuracy of which was assessed with DNA-based polymerase chain reaction and automated immunoanalysis. 305 out of 2622 tested samples with 78 different serotypes were identified as Salmonella-contaminated products. Results also indicated a steady increase in Salmonella incidence, along with a corresponding increase in Salmonella isolate and serotype diversity since 2007. This prevalence of Salmonella-contaminated feed stocks presents a potential risk to public health.