Presence of salmonella, escherichia coli O157 and campylobacter in small-ruminants
Hanlon, Keelyn E.
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Meat derived from goats and lambs is an important and often underappreciated protein source in the U.S., but it is especially important in developing countries challenged with food insecurity. While extensive studies have been conducted examining pathogen prevalence in beef, pork and poultry species, less research is available about pathogen presence in small-ruminants. In developing countries, small-ruminants often co-exist with humans in living and work conditions, making cross contamination and frequent contact with fecal matter a common occurrence. In the U.S., the popularity of small ruminants as a protein source is growing. Additionally, many small-ruminants are considered pets presenting potential pathogen exposure to family members. Salmonella, Campylobacter and Escherichia coli O157 are all pathogens of concern known to be found in livestock. Understanding the presence of these pathogens in small-ruminants can influence processing method improvements for these species to minimize food safety risks. This study had three main objectives: 1) To determine pathogen prevalence in small-ruminants on hide and fecal samples collected from U.S. and international sources; 2) Salmonella prevalence in small-ruminant carcass surface and retail samples from the U.S. and international sources; and 3) Salmonella prevalence found in lymph nodes from sheep and goats. Samples were collected at abattoirs and farms located in California, New Mexico, Texas, the Bahamas and Mexico over a 14 month period. Samples were processed using a combination of traditional culturing methods and real-time PCR. All presumptive positive samples were confirmed by isolation and biochemical analysis. Campylobacter, E. coli O157 and Salmonella were detected in samples collected from both sheep and goats. Salmonella was detected in 17.11% of hide samples, 13.91% of fecal samples, 16.82% of retail samples, and 1.94% - 9.62% of lymph nodes and up to 5.20% on carcass surfaces. E. coli O157 was present in 1.50% of hide samples and 15.30% of fecal samples. Campylobacter was found in 80.68% of fecal samples. The results indicate the presence of potential pathogens from small-ruminant sources. Further study of the trends of these pathogens through season, geographical location and management conditions, as well as control measures, are important to better understand the risks associated with these pathogens present in small-ruminants.