A comparison of the original Rappaport medium (R medium) and the Rappaport–Vassiliadis medium (RV medium) in the isolation of salmonellae from meat products

Abstract

SUMMARY: The Rappaport–Vassiliadis enrichment medium (RV medium)in 10 ml quantities (RV/43 °C, 10 ml) inoculated with 0·1 ml of pre-enrichment medium (P medium) was found more efficient in the isolation of salmonellae from 409 pre-enriched samples (mainly meat products), than the original Rappaport medium incubated at 43 °C (R/43 °C) and the RV medium in 5 ml quantities (RV/43 °C, 5 ml) inoculated with 0·01 ml of P medium (P< 0·001, in both instances). Therefore, the inoculum from pre-enriched foods should not be less than 0·l ml in 10 ml of RV medium.The RV/43°, 10 ml was also better (P< 0·01) in detecting samples containing salmonellas than the original Rappaport medium incubated at 37 °C (R/37 °C, 10 ml) and the modification R25 of R medium incubated at 37 °C. The R25 modification was used in 10 ml quantities (R25/37 °C, 10 ml) inoculated with 0·1 ml of P medium and in 5 ml quantities (R25/37°, 5 ml) inoculated with 0·01 ml of P medium. The last two R25 procedures were of the same efficiency in isolating salmonellas from meat products.