Thermo Scientific™ Oxoid™ Rappaport-Vassiliadis Soya Peptone Broth (Dehydrated)

The Rappaport-Vassiliadis Soya Peptone Broth (RVS Broth) is a highly selective enrichment medium used for isolating Salmonella spp. from food, environmental, and fecal samples. This medium leverages the physiological characteristics of Salmonella to inhibit non-target organisms, offering reliable results in microbiological testing.

Key Features

1. Selective Enrichment:
   • Utilizes malachite green, magnesium chloride, and low pH to selectively promote the growth of Salmonella spp. while suppressing competing microorganisms.
2. Optimized Composition:
   • Includes di-potassium hydrogen phosphate to buffer the medium and maintain stability.
   • Contains clarified concentrations of magnesium chloride for enhanced selectivity and reliability.
3. Broad Applications:
   • Effective for food and environmental microbiology testing.
   • Can be directly inoculated with fecal samples without the need for pre-enrichment.

Typical Composition (g/L)

Preparation Instructions

1. Suspend 26.75 g of RVS Broth in 1 L of distilled water.
2. Heat gently to dissolve the powder completely.
3. Dispense 10 mL into screw-capped bottles or tubes.
4. Sterilize by autoclaving at 115°C for 15 minutes.
5. Store the prepared medium at 2–8°C.

Applications

1. Food and Environmental Testing:
   • Detect Salmonella spp. in raw and processed food samples.
   • Isolate Salmonella spp. from environmental samples like water or surfaces.
2. Clinical Microbiology:
   • Enrich and isolate Salmonella spp. from human fecal samples.

Technique

Food and Environmental Samples:

1. Pre-enrichment:
   • Prepare Buffered Peptone Water (CM0509) or ISO Buffered Peptone Water (CM1049).
   • Add 25 g of sample to 225 mL of pre-enrichment broth.
   • Incubate at 37°C for 16–20 hours.
2. Transfer:
   • Transfer 0.1 mL of the pre-enriched culture into 10 mL of RVS Broth.
   • Incubate at 42 ± 1°C for 24 hours.
3. Subculture:
   • Streak onto selective agar plates, such as MLCB Agar (CM0783) or Modified Brilliant Green Agar (CM0329).
   • Incubate at 35°C for 18–24 hours.

Fecal Samples:

1. Direct Inoculation:
   • Add 1–2 loopfuls of liquid feces (or fecal saline emulsion) to 10 mL of pre-warmed RVS Broth.
   • Incubate at 42 ± 1°C for 24 hours.
2. Subculture:
   • Streak onto selective agar plates for identification.

Storage and Shelf Life

• Dehydrated Medium:
  • Store at 10–30°C in a sealed container.
  • Use before the expiry date.
• Prepared Medium:
  • Store at 2–8°C, protected from light.

Appearance

Quality Control

Precautions

1. Limitations:
   • Not recommended if Salmonella Typhi is suspected.
2. Optimal Conditions:
   • For best recovery, incubate the enrichment broth at 42 ± 1°C.
3. Shelf Life:
   • Discard prepared media if contamination or deterioration is observed.

Advantages

1. Highly Selective:
   • Effective in isolating Salmonella spp. even in complex samples.
2. Optimized Formula:
   • Enhanced buffering and magnesium chloride levels improve reliability.
3. No Pre-Enrichment for Fecal Samples:
   • Direct inoculation saves time and simplifies workflows.

Applications Summary

• Food Safety Testing: Detects Salmonella spp. contamination in raw and processed food.
• Environmental Monitoring: Isolates Salmonella spp. from water and other environmental samples.
• Clinical Diagnostics: Enriches Salmonella spp. from fecal samples for further identification.

The RVS Broth is a reliable and selective medium for microbiological laboratories conducting food safety, environmental testing, and clinical diagnostics. Let me know if you need further details or related comparisons!