A study of the relative efficiencies of three commercially available dehydrated Rappaport-Vassiliadis media

The relative efficiencies of three commercially available dehydrated Rappaport-Vassiliadis media have been compared with a similar medium prepared from individual constituents in our own laboratory. An inoculation ratio of 1:100 was found to be optimal for each of the media tested. Laboratory produced RV-medium was significantly better than the three commercial preparations after 24 h incubation. However, when the duration of incubation was extended to 48 h, there was no significant difference in the number of salmonella isolates obtained when using our own RV medium and that produced by Oxoid Ltd and Difco Ltd (P greater than 0.05). All of these three media were, however, significantly more effective than the medium produced by Lab.M. (P less than 0.01).