Purpose: The aim of the study was to evaluate the performance of the Salmonella test system compared to the FDA BAM (Chapter 5 Salmonella) for the detection of Salmonella spp. in shrimp and catfish.
Methods: Shrimp and catfish samples (25 g) were inoculated with a low level, (1 cell per sample) of Salmonella Typhimurium ATCC 14028. Twenty-five samples, 20 low-level inoculated and 5 non-inoculated samples, of each matrix were analyzed by both methods. Samples for the test method were enriched in 225 ml of primary media, transferred to secondary media, and evaluated with test strips at a total time of just 22 h. For the FDA BAM method, samples were enriched and incubated in Lactose broth, transferred to Tetrathionate broth and Rappaport-Vassiliadis broth, and struck to HE and XLD agars for a total of 62-76 h.
Results: The test method detected 11 and 10 low-level inoculated shrimp and catfish samples, respectively, while the FDA BAM reference method detected 12 and 7 samples as positive. All samples were confirmed by the cultural method. There was no significant difference between the two test methods and equivalent performance was demonstrated. The overall Chi-square was 0.197 resulting in 111% accuracy, 100% average sensitivity and 100% average specificity.
Significance: The Salmonella test system detects low levels of Salmonella spp. in shrimp and catfish in as little as 22 hours. This should enable food producers to quickly and efficiently identify Salmonella spp. in a variety of seafood types, with reduced time and labor inputs while maintaining test method performance compared to the cultural reference method.