Rappaport-Vassiliadis (MSRV) Medium Semi-Solid is a modification of Rappaport-Vassiliadis Soy Broth for detecting motile Salmonella spp. in faeces and food products.[1]

The original research on MSRV Medium revealed a semi-solid could be used as a rapid and sensitive test for isolating motile Salmonella spp. from food products following pre-enrichment or selective enrichment.[2]

The semi-solid medium allows motility to be detected as halos of turbid growth around the original point of inoculation.

The peptones are to provide vitamins, nutrients and nitrogen to encourage growth of Salmonella spp.

The salt maintains the osmotic balance and potassium dihydrogen phosphate is a buffer for stabilising the pH of the medium.

Malachite green is included as a selective agent that inhibits Gram-positive organisms and some Gram-negative organisms.

References

(1) ISO 6579-1:2017. Microbiology of the food chain – Horizontal method for the detection, enumeration and serotyping of Salmonella – Part 1: Detection of Salmonella spp.

(2) De Smedt J.M., Bolderdikj R., Rappold H. and Lautenschlaeger D. 1986. Rapid Salmonella Detection in Foods by Motility Enrichment on a Modified Semi-Solid Rappaport-Vassiliadis Medium. J. Food Prot. 49:510-514