EVALUATION OF IMMUNOMAGNETIC SEPARATION IN COMBINATION WITH MODIFIED SEMISOLID RAPPAPORT-VASSILIADIS MEDIUM AND RAMBACH AGAR FOR THE ISOLATION OF SALMONELLA

The ability of polymagnetic beads coated with Salmonella antibodies to enhance detection of Salmonella using Modified Semi-solid Rappaport V assiliadis (MSRV) medium and Rambach agar was evaluated. Inoculation o f the MSRV medium with pre-enriched buffered peptone water (BPW) resul ted in the isolation of Salmonella from 60% of raw poultry samples. Ca pture of the Salmonella with the beads and inoculation of the beads on to MSRV medium resulted in the isolation of Salmonella from 62% of the samples. If the pre-enriched BPW was centrifuged and the pellet was r esuspended in 1 ml of BPW before capture of the Salmonella with the be ads and inoculation of the beads onto MSRV medium, Salmonella were iso lated from 65% of the samples. Direct plating of the beads to Rambach agar after capture of Salmonella from the pre-enriched BPW, but withou t selective enrichment in the MSRV medium, resulted in low recovery ra tes of Salmonella. Plating of pure cultures of Salmonella belonging to subspecies IIIa acid IIIb onto Rambach agar resulted in colonies with an atypical appearance.