Purpose: To demonstrate the equivalence of Assurance GDS for Salmonella Tq to the reference culture methods for the detection of Salmonella in selected cocoa and chocolate containing foods.
Methods: Three food matrices (cocoa powder, milk chocolate and chocolate cake) representing the chocolate and confectionaries category were included in the study. 20 cocoa powder samples were inoculated with low levels of Salmonella, 40 samples were inoculated with high levels of Salmonella and 10 uninoculated samples were included as controls. 20 milk chocolate and chocolate cake samples were inoculated with low levels of Salmonella, 20 samples were inoculated with high levels of Salmonella and 5 uninoculated samples were included as controls. 25 g samples of cocoa powder and milk chocolate were enriched with a 1:10 sample to media ratio in UHT milk + Brilliant Green media for 18 – 24h at 36°C. 25 g samples of chocolate cake were enriched with the same ratio, temperature and time but in Buffered Peptone Water (BPW). All samples were analyzed using Assurance GDS for Salmonella Tq according to the directions for use and reference culture methods. For all samples, the reference method used was ISO 6579:2002.
Results: After analysis the data showed that for all three cocoa containing food matrices, McNemar’s chi-square showed the performance of Assurance GDS Salmonella was equivalent to the reference culture method.
Significance: This new detection method for cocoa-containing foods gives customers a faster option for testing Salmonella than culture methods, while retaining the necessary accuracy for this difficult food matrix.