Rappaport-Vassiliadis Soya (RVS) Broth | AS-1338

Rappaport Vassiliadis Broth (RVS) — also known as Rappaport-Vassiliadis Soya Peptone Broth — is the international standard selective enrichment medium for the isolation of Salmonella spp. from food, animal feed, environmental samples, water, and pharmaceutical non-sterile products. It is prescribed as the secondary enrichment step in ISO 6579-1:2017 and is harmonised across EP 2.6.13, USP <62>, and JP Chapter 4.05.

RVS Broth achieves Salmonella selectivity through three synergistic mechanisms:

• Malachite green (0.036 g/L): Triphenylmethane dye that inhibits Gram-positive bacteria and most competing Gram-negatives at this concentration. Salmonella exhibits a unique tolerance to malachite green due to its active efflux pump systems (AcrAB-TolC) that expel the dye before it reaches inhibitory intracellular concentrations.
• Magnesium chloride (13.4 g/L) — elevated osmolarity (~1,400 mOsm/kg): The high Mg²⁺ concentration creates osmotic stress that inhibits most competing flora including E. coli, coliforms, and Proteus spp. Salmonella tolerates this environment through superior osmoregulation via OmpC/OmpF porin switching and compatible solute accumulation.
• Acidic pH (5.2): The low pH further suppresses most competing Gram-negative bacteria. Salmonella remains viable at pH 5.2 via its Acid Tolerance Response (ATR) system — including inducible acid resistance mechanisms — while competitors are inhibited.

The soy peptone base provides a balanced amino acid and vitamin profile — particularly rich in branched-chain amino acids — that preferentially supports Salmonella growth under the selective conditions of the medium. The incubation temperature of 41.5 °C (ISO 6579-1 standard) provides an additional thermal selectivity that favours Salmonella over psychrotrophic background flora.

Transfer 0.1 mL of BPW pre-enrichment to 10 mL RVS Broth (1:100 inoculation ratio per ISO 6579-1:2017).

• Secondary selective enrichment in ISO 6579-1:2017 Salmonella detection workflow
• Broad food matrices: raw meat, poultry, eggs, dairy, spices, herbs, dried foods, pet food
• Animal feed and raw material screening per ISO 6579-1
• Environmental swab enrichment from food production facilities

• Salmonella testing of non-sterile pharmaceuticals — EP 2.6.13, USP <62>, JP Chapter 4.05
• Herbal medicines, botanical excipients, and raw material testing
• Finished product release testing per pharmacopoeial harmonised method

• Salmonella enrichment from drinking water, wastewater, surface water — ISO 19250:2010
• Environmental monitoring from manufacturing and processing facilities
• Sewage sludge and biosolids Salmonella screening

1. Dissolve 26.75 g per litre of purified water with gentle agitation at room temperature. Do NOT heat to dissolve.
2. Dispense: 10 mL per tube (for 0.1 mL BPW inoculum per ISO 6579-1) or as required.
3. Autoclave at 115 °C for 15 minutes ONLY.
4. Cool to room temperature. Appearance: bluish-green, clear liquid.
5. Store at 2–8 °C, protected from light. Use within 3 months.

AuSaMicS AS-1338 is an Australian-manufactured equivalent to the following international products. All equivalents comply with the same ISO 6579-1:2017, EP/USP/JP pharmacopoeial specification.

Ordering AuSaMicS AS-1338 instead of imported equivalents: same-week dispatch from Melbourne, full COA/SDS/TDS documentation, and local technical support.

Malachite green (0.036 g/L): Inhibits Gram-positive organisms and most competing Gram-negatives. Salmonella resists via AcrAB-TolC efflux pumps.

MgCl₂·6H₂O (13.4 g/L) — ~1,400 mOsm/kg: Osmotic stress selectively inhibits E. coli, coliforms, and Proteus. Salmonella compensates via OmpC/OmpF regulation and compatible solute accumulation.

Acidic pH (5.2): Additional selective pressure. Salmonella survives via its Acid Tolerance Response (ATR) system; most Gram-negative competitors cannot.

Soy peptone + 41.5 °C incubation: Thermal selectivity combined with balanced amino acid nutrition preferentially supports Salmonella enrichment.

Inoculum: ≤100 CFU per ATCC strain | Incubation: 41.5 °C, aerobic (ISO 6579-1:2017 conditions)

• Secondary enrichment only — requires prior non-selective pre-enrichment (BPW or equivalent)
• Autoclave at 115 °C only — 121 °C irreversibly degrades malachite green
• S. typhi may be partially inhibited — use Selenite Cystine Broth as parallel enrichment for typhoid investigation
• Positive enrichments must be subcultured to selective agar + confirmed biochemically/serologically

Uninoculated medium: Do NOT dispose to drain (H400 aquatic toxicity). Collect in labelled chemical waste. Dispose via licensed chemical waste contractor.

Inoculated medium: Autoclave at 121 °C / 30 min to inactivate Salmonella. Collect as chemical waste — consult local EPA for malachite green disposal requirements.

Inoculum ≤100 CFU | Incubation: 41.5 °C, aerobic, 24 ± 3 h (ISO 6579-1:2017)