Rappaport-Vassiliadis Salmonella (RVS) broth is a selective medium, which is used for the enrichment of Salmonella spp, following a pre-enrichment of the specimen in a suitable medium (e.g. BPW).
RVS broth contans: Soya peptone MgCl2, NaCl phosphate malachite green The final pH should be 5.2.
The selectivity of the medium is due to the presence of malachite green, high osmotic pressure, and a low pH. The high concentration of magnesium chloride raises osmotic pressure, and in combination with malachite green, inhibits bacteria other than Salmonella spp. The low pH of the medium increases selectivity by inhibiting accompanying flora, including intestinal bacteria.