Purpose: The objective of this study was to evaluate the performance of the rapid 3M™ Molecular Detection System (MDS) in comparison with the ISO method for detecting healthy, injured and naturally contaminated Salmonella spp. on locally produced duck wings, bean sprouts and fish balls.
Methods: Healthy and injured Salmonella spp. were inoculated on food matrix at 100 and 101 CFU/25g. Injured cells were prepared by heat treatment for duck wings and fish balls, and chlorine treatment for bean sprouts. Un-inoculated samples were used as control along with an additional of 30 naturally contaminated samples as validation for each food matrix. A total of 360 samples were subjected to both the rapid and ISO methods with reported qualitative results compared.
Results: Regardless of inoculum levels, the detection by the rapid method showed 100% sensitivity and specificity for both inoculated and un-inoculated samples compared with the ISO method, except for bean sprout samples, which were inoculated with 100 CFU/25g of injured Salmonella spp. The validation study also showed that the rapid method could provide 91% sensitivity and 95% specificity for naturally contaminated samples.
Significance: MDS was demonstrated to be a cost effective method, as this system could provide rapid, accurate detection of healthy, injured and naturally contaminated Salmonella spp. on duck wings, bean sprouts and fish balls in less than 48 h. This study also suggests that a secondary enrichment may be necessary to enhance the performance of the rapid method for some challenging food matrices with a high microbial load.