Collaborative study of the International Office of Cocoa, Chocolate and Sugar Confectionery on Salmonella detection from cocoa and chocolate processing environmental samples.

A comparative collaborative study was performed in 13 laboratories to evaluate the use of motility enrichment on Modified Semisolid Rappaport-Vassiliadis medium for rapid Salmonella detection from food-processing environmental samples. Artificially contaminated chocolate scrapings and naturally contaminated cocoa bean dust samples were used in the study. Pre-enrichment was performed in buffered peptone water with added casein and malachite green oxalate. Motility enrichment was compared with a conventional cultural procedure using Rappaport-Vassiliadis broth and selenite cystine broth as selective enrichment. The productivity of motility enrichment was 93.5% compared to a productivity of the cultural procedure of 92%. Statistical analysis showed that there was no significant difference between the two procedures. Modified Semisolid Rappaport-Vassiliadis medium is a sensitive and simple diagnostic tool for the microbiological safety evaluation of food-processing environments.