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 cocoa powder.
Methods: Cocoa powder samples (25g) were inoculated with a low level, (3 cells per sample) of Salmonella Enteritidis ATCC 13076. Twenty five samples, 20 low-level inoculated and 5 non-inoculated samples, 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 hours and confirmed using HE and XLD agars. For the FDA BAM method, samples were enriched and incubated in skim milk supplemented with brilliant green solution, transferred to Tetrathionate broth and Rappaport-Vassiliadis broth, and struck to HE and XLD agars for a total of 66-78 hours.
Results: The test method detected 10 low-level inoculated cocoa powder samples, while the FDA BAM reference method detected 6 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 1.625 resulting in 167% relative accuracy, 100% sensitivity and 100% specificity.
Significance: The Salmonella test system detects low levels of Salmonella spp. in cocoa powder in as little as 22 hours. RapidChek will provide users with a rapid, reliable, cost effective tool for monitoring and controlling Salmonella species in cocoa powder.