Description
Rappaport medium was first described in 1956. Tryptone provided nutritive properties, magnesium chloride, malachite green and low pH acted as selective agents and it also contained the buffering agent potassium di-hydrogen phosphate and sodium chloride. At that time, it was not as widely used as selenite or tetrathionate medium.
In 1970, Vassiliadis et al., reduced the malachite green content of the original formula, and used it as a secondary selective enrichment medium. Over a period of eight years the malachite green content was reduced still further to a level of 0.004%, by Vassiliadis and his associates. The medium became known as R 10, and later as Rappaport-Vassiliadis medium (RV), with a recommended incubation temperature of 43°C.
In 1983, van Schothorst and Renaud, whilst evaluating Rappaport-Vassiliadis medium (RV) found that the substitution of soy peptone for tryptone enhanced its performance, and the Amyl Media formulation conforms to this modification. Some of the reported advantages of this medium are its reproducibility batch to batch, and its relative stability on storage of the prepared product, for at least one month. It has been reported that it performs best with the addition of small inocula from pre-enrichment broth samples or small samples which have not been pre-enriched. Fricker suggested a dilution factor in the order of 1 in 100 to 1 in 2000 sample to enrichment broth, would prevent interference of the sample with the selective properties of Rappaport-Vassiliadis medium.
