Purpose: The objective of this study was to determine the prevalence of Salmonella and E. coli O157 in small-ruminants across the United States.
Methods: Hide swabs (N = 167) and fecal samples (N = 169) were collected from sheep and goats at small abattoir facilities in New Mexico and Texas, from February through December 2014. Hide swabs were taken post exsanguination at four sampling locations (rump/inside leg round, midline/flank, foreshank, and neck/breast. Fecal samples were collected aseptically from the gastrointestinal tract post-evisceration. Hide swabs and fecal samples were analyzed for Salmonella using selective enrichment broths (Rappaport-Vassiliadis and Tetrathionate) and two different selective and differential media (Xylose Lysine Tergitol 4). E. coli O157 analysis was done by enrichment of hide swabs and fecal samples in Gram-negative broth with added antibiotics (8 µg/ml of vancomycin, 50 ng/ml of cefixime and 10 µg/ml of cefsulodin) to suppress background microflora. Samples were then subjected to standard immunomagnetic separation (IMS) procedures and plated onto CHROMagar O157 agar with 2.5 mg/l tellurite. A Chi-square (PROC FREQ) test was performed using SAS.
Results: Salmonella was detected in 21.56% (n = 36) of hide swabs and 9.47% (n = 16) of fecal samples. E. coli O157 was detected in 22.94% (n = 25) of fecal samples and 1.83% (n = 2) of hide swabs.
Significance: Pathogens in this study were readily isolated from these samples indicating a potential food safety problem if not properly controlled during slaughter. It will be important to investigate control measures for these pathogens during processing and validate their effectiveness in processing settings in order to ensure public health.