Detection and Isolation of Salmonella spp. in Animal Feeds from 2007-2011

Yi-Cheng Hsieh, Kyung-Min Lee, Toni Poole, Mick Runyon, Ben Jones, Timothy J Herrman


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 United States (US) Food and Drug Administration (FDA) promulgated regulations prohibiting Salmonella contamination in feed and has since published a draft guidance document expressing their current strategy involving regulatory oversight of Salmonella contamination in feed.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 (OTSC) initiated the broad surveillance of Salmonella spp. in 2007 in response of 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 calendar years of 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 (PCR) and automated immunoanalysis. Three hundred and five 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.


Salmonella, Animal feed, Food illness, Pathogen detection, Surveillance

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