Purpose: To determine the prevalence of Salmonella spp. in ground beef obtained from butcher shops in Guadalajara, México, using the 3M™ Molecular Detection Assay (MDA) for Salmonella in comparison to the USDA/FSIS MLG 4.08 reference method.
Methods: Ninety-three ground beef samples were obtained for the study. The Guadalajara city was divided in seven geographical zones for data analysis according to the number of butcher shops in each zone. Each sample (25 g) was homogenized in 225 ml of BPW-ISO and incubated for 24 h, followed by a 75-min analysis with the 3M MDA for Salmonella. All positive and negative results by MDA were confirmed following the USDA/FSIS MLG 4.08 method.
Results: Seventy-four out the 93 ground beef samples tested positive for Salmonella (79%). The percentage of positive samples for the Minerva, Olímpica, Oblatos, Industrial, Tetlán, Huentitán and Centro zones was 57%, 61%, 77%, 78%, 84%, 93% and 100%, respectively. All positive samples by 3M MDA were biochemically and serologically confirmed, and there were no false negative results observed, reflecting a 100% accuracy, sensitivity and specificity in comparison to the reference method.
Significance: Results suggest that there is significant prevalence of Salmonella in ground beef obtained from butcher shops in Guadalajara, México. The 3M MDA proved to be a reliable method for detection of Salmonella spp. in ground beef, delivering fast and accurate results.