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

Abstract

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.

Comparison of the MSRV method with an in-house conventional method for the detection of Salmonella in various high and low moisture foods

“…Experience within Nestle UK Ltd has shown that the use of selenite cystine broth as an additional selective medium does not result in a significantly higher level of positive results (unpublished data). This agrees with the findings of IOCCC collaborative trials (De Smedt and Bolderdijk 1990;De Smedt et al 1991). For this reason and due to the safety hazards associated with sodium biselenite, the Nestle UK Ltd modification uses RV as the sole selective enrichment broth.…”

Evaluation of a Multiplex PCR assay for simultaneous identification ofSalmonellasp.,SalmonellaEnteritidis andSalmonellaTyphimurium from environmental swabs of poultry houses

“…This MSRV–PCR assay is easy to perform and suitable for analysis of a large number of samples each day. The sensitivity of the MSRV medium is higher as only 60 Salmonella ml −1 pre‐enrichment broth are necessary to give a positive result on an MSRV agar plate according to De Smedt & Bolderdijk (1990). It reduces the number of analyses and hence, the cost per test because only those samples with a migratory zone on an MSRV agar plate are subjected to the m‐PCR.…”

Comparison of the MSRV Method With an in-House Conventional Method for the Detection of Salmonella in Various High and Low Moisture Foods

“…typhimurium, grew well. De Smedt and Bolderdijk (1990) attributed their failure to recover spray dried Salm. typhimurium from gelatin reference capsules on MSRV to the fact that the organisms did not fully develop flagella and so did not migrate through the semi-solid medium.…”