Rappaport Vassiliadis HiCynth™ Medium

Principle And Interpretation

Rappaport Vassiliadis Medium is designed according to the revised formulation by Van Schothorst et al (1) and is recommended for the selective enrichment of Salmonellae from food and environmental specimens. Present medium is a modification of the Rappaport Vassiliadis Enrichment Broth described by Van Schothorst and Renauld (2). Rappaport Vassiliadis HiCynth™ Medium is modified using chemically defined peptones, free from animal and vegetable peptones to avoid BSE/TSE risks associated with animal peptones. Addition of magnesium chloride to the medium was reported by Peterz et al (3). Salmonella species can be isolated from human faeces without pre-enrichment by using this medium. Salmonella generally survive at little high osmotic pressure, grow at slightly low pH and are resistant to malachite green compared to other bacteria.

The medium contains HiCynth™ Peptone No.3 which provides nitrogeneous compounds and carbon compounds, long chain amino acids and other essential growth nutrients. Magnesium chloride raises the osmotic pressure in the medium. Malachite green is inhibitory to organisms other than Salmonellae. The low pH of the medium, combined with the presence of malachite green and magnesium chloride, helps to select for the highly resistant Salmonella species. Potassium phosphate buffers the medium to maintain the constant pH. Sodium chloride maintains the osmotic balance.