Product Overview
Use: Rapport-Vassiliadis R10 Broth is a broth medium used for the selective enrichment of Salmonella sp. from meat products, feces, and sewage polluted water.
Description: Rappaport-Vassiliadis R10 Broth is a new enrichment medium for salmonellas based upon a formulation developed by Rappaport et al. The selectivity of this medium for Salmonella is created by the addition of a high concentration of magnesium chloride, the dye malachite green and the lowering of pH. Salmonella are more resistant to high osmotic pressure and are able to grow in hypertonic solutions. Growth of intestinal bacteria is inhibited in hypertonic solutions. Vassiliadis et al. modified the original formula by lowering the concentration of malachite green and recommending incubation at 43°C. Lowering the incubation temperature to 41.5 ± 0.1°C is now recommended since it enhances growth of Salmonella and allows for only a 24 hour incubation time. Rappaport-Vassiliadis R10 Broth cannot be used for the isolation of some strains of Salmonella, specifically S. typhi and S. choleraesuis, since they are inhibited by malachite green. If the isolation of multiple serotypes from environmental samples is required, it is recommended that other enrichment broths such as Tetrathionate Broth or Selenite F broth be used in conjunction with the R10 Broth.
Formula* per Liter:
- Tryptone ................................................. 4.54g
- Sodium Chloride ....................... 7.2g
- Potassium Dihydrogen Phosphate ..... 1.45g
- Malachite Green Oxalate ..... 0.036g
- Magnesium Chloride, Anhydrous ........13.4g
Final pH: 5.1 ± 0.2 at 25.0°C
* Grams per liter may be adj. or formula supplemented to obtain desired performance
Preparation: Mix 26.6 grams of the medium in one Liter of purified water until evenly dispersed. Heat with repeated stirring and boil for one minute to dissolve completely. Distribute and autoclave at 116.0°C for 15 minutes.
Quality Control Specifications:
- The powder is homogeneous, free flowing and beige to pale green.
- Visually the prepared medium is clear and blue.
- Expected cultural response after 24 hours at 41.5°C and subcultured to Brilliant Green Agar and incubated overnight.
Organism                                                                    Result
Escherichia coli ATCC 25922Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Inhibited
Salmonella enteritidis ATCC 13076Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Good growth
Salmonella typhimurium ATCC 14028Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Good growth
Storage: Store the sealed bottle containing the dehydrated medium at 2 to 30.0°C. Once opened and recapped, place the container in a low humidity environment at the same storage temperature. Protect it from moisture and light. The dehydrated medium should be discarded if it is not free flowing or if the color has changed from the original light pinkish-beige color.