IMS: a new selective enrichment technique for detection of Salmonella in foods

In a study designed to evaluate the performance of Dynabeads Anti-Salmonella, immunomagnetic separation (IMS) followed by plating (IMS-Plating) proved far superior to the conventional ISO Salmonella methodology and the Modified Semi-solid Rappaport-Vassiliadis (MSRV) method. Salmonella species were isolated and detected from 135 out of the 180 diverse poultry samples by IMS analysis as against 98 by the conventional method and 33 by the MSRV technique. All results were confirmed biochemically and serologically. It appeared from the data generated that some of the salmonellae isolated using IMS were greatly inhibited in Rappaport-Vassiliadis enrichment broth at 42 degrees C and to a lesser extent in selenite cystine broth at 37 degrees C. A moderately selective plating medium like XLD proved to be better in isolating these possible sensitive wild-type strains of salmonellae than the more selective BGA.