No abstract

SUMMARYA total of 745 samples of chicken giblets was cultured to determine the relative efficiency of a commercially available Rappaport-Vassiliadis medium (RV-Oxoid). Experiments to determine the optimum inoculation ratio showed that 1: 100 was superior to the other ratios tested. Comparison of RV-Oxoid with standard RV and RV-medium prepared using soya peptone (RV-soya) showed that after 24 h RV-soya was significantly better than RV-Oxoid (P < 0-05), although there was no significant difference between standard RV and RV-Oxoid. Furthermore, when the duration of incubation was extended to 48 h there was no significant difference between the three media (P > 0 25).We conclude that RV-Oxoid is a satisfactory product for the isolation of salmonellae from poultry, providing that it is inoculated at a ratio of 1: 100 and is incubated for 48h. Its use can therefore be recommended to laboratories who wish to use a dehydrated medium.

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).