This monograph has been assessed by members of the IUMS–ICFMH Working Party on Culture Media and given ‘Approved’ status.

The efficiency of Rappaport–Vassiliadis enrichment medium for salmonellae is based on the following: (a) the ability of Salmonella spp. to multiply at relatively high osmotic pressures (concentration of magnesium chloride hexahydrate of 28.6 g L⁻¹ in the final medium), at relatively low pH values, at a high temperature and with modest nutritional requirements; and (b) the suppression of the toxic effect of malachite green towards salmonellae by the presence of magnesium chloride. The medium was first proposed by Rappaport et al. (1956) for the enrichment of selected Salmonella serotypes and was later modified by Vassiliadis et al. (1976, 1983), reducing the concentration of malachite green to one third. Owing to the unusual method of preparation, there has been some confusion about the concentration of magnesium chloride: a final concentration of 35 g L⁻¹ of medium is too high (Peterz et al., 1989; Busse, 1995). The ratio of inoculum to broth is normally 1:100 and the incubation temperature is 41–42°C because some strains, particularly Salmonella Dublin, do not grow at 43°C (Peterz et al., 1989).