Purpose: To evaluate the performance of the 3M Molecular Detection Assay Salmonella through comparison with a cultural method for artificially and naturally contaminated feed and pet food matrices, including: (1) Raw material (Soybean, Fish, Rice Bran Oil and Premix); (2) Canned; (3) Feed with supplements and vitamins.
Methods: All samples were weighed into 25-g portions and enriched in 225 ml 3M Buffered Peptone Water ISO. Sample enrichments were incubated at 37 ± 1°C for 18 - 24 h and then tested by two methods: (a) 3M Molecular Detection Assay Salmonella (including Matrix Control); and (b) cultural method ISO 6579. Presumptive positive molecular results were confirmed onto XLD and HE agars and typical colonies subjected to biochemical confirmation following ISO 6579 procedures.
Results: One hundred ninety-five (195) samples were tested in total; 58 samples were spiked with a low level (3 - 18 CFU) of Salmonella Typhimurium; 137 samples were tested with natural contamination. Overall, 3M Molecular Detection System showed 98.25% sensitivity, 98.28% specificity, 98.97% accuracy and no significant difference from the reference method using the Chi-square statistic.
Significance: For all feed and pet food matrices evaluated, the 3M™ Molecular Detection Assay Salmonella demonstrated comparable results to the reference methods for the rapid, automated detection of Salmonella.