Collaborative Study of the International Office of Cocoa, Chocolate, and Sugar Confectionery on the Use of Motility Enrichment for Salmonella Detection in Cocoa and Chocolate.

A comparative collaborative study was performed in 15 laboratories to validate the use of motility enrichment on Modified Semisolid Rappaport-Vassiliadis (MSRV) medium for Salmonella detection in cocoa and chocolate products. The use of MSRV was compared with a cultural procedure using Rappaport-Vassiliadis broth and selenite cystine broth as selective enrichments. Artificially contaminated milk chocolate samples as well as Salmonella reference capsules added to Salmonella-free cocoa and milk chocolate were used as test samples. Motility enrichment produced 347 positive test results compared to 320 for the cultural procedure. For samples containing a lactose positive Salmonella strain, motility enrichment was far more productive than the cultural procedure, while for the other samples no significant statistical difference in the productivity of both procedures was observed at the 5% level.