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R2A Broth | Low-Nutrient Water Enrichment Medium | Ausamics Cat: AS-1397
$39.00 AUD
Documentation
R2A Broth (Reasoner's 2A Broth)
Low-Nutrient, Non-Selective Liquid Medium for Heterotrophic Bacteria Recovery from Treated Drinking Water & Environmental Samples | Cat. No. AS-1397
AS-1397 pH 7.2 ± 0.2 Suspend 3.12 g/L ✓ APHA 9215 · ISO 8245 🇦🇺 Melbourne
Cat. No.
AS-1397
Suspend Rate
3.12 g/L
Final pH
7.2 ± 0.2
Format
Dehydrated → Broth
📄 Full DocumentationCOA, TDS & SDS every batch
🇦🇺 Australian StockNo import delays
⚡ Same-Week DispatchMelbourne warehouse
🔬 Technical SupportDirect from our team
Overview
R2A Broth (Reasoner's 2A Broth) is a low-nutrient, non-selective liquid culture medium originally formulated by Reasoner and Geldreich (1985) for the recovery and cultivation of heterotrophic bacteria from treated drinking water and environmental samples. Its deliberately diluted nutrient composition supports the growth of oligotrophic, stressed, and slow-growing microorganisms that are frequently inhibited on conventional nutrient-rich media.
AS-1397 is the internationally recognised broth format for heterotrophic plate count (HPC) enrichment, Most Probable Number (MPN) assays, biofilm studies, and environmental microbial ecology. It is validated per APHA Standard Methods 9215, US EPA Method 9215, ISO 8245, and ASTM D9217.
Key Features
Low-nutrient formulation (3.12 g/L total) — promotes recovery of oligotrophic and stressed bacteria
Non-selective — supports a wide variety of environmental and water-borne microorganisms
Liquid broth format — ideal for enrichment cultures, MPN assays, suspension cultures, and biofilm systems
Balanced 8-component formula — includes pyruvate, soluble starch, and amino acid sources for diverse metabolic types
Standardised — validated per APHA 9215, US EPA 9215, ISO 8245, and ASTM D9217
Compatible with 7–14 day incubation — formulated for extended oligotrophic culture without medium deterioration
Non-selective — supports a wide variety of environmental and water-borne microorganisms
Liquid broth format — ideal for enrichment cultures, MPN assays, suspension cultures, and biofilm systems
Balanced 8-component formula — includes pyruvate, soluble starch, and amino acid sources for diverse metabolic types
Standardised — validated per APHA 9215, US EPA 9215, ISO 8245, and ASTM D9217
Compatible with 7–14 day incubation — formulated for extended oligotrophic culture without medium deterioration
Applications
💧
Drinking Water HPC
Heterotrophic plate count, APHA 9215
🧪
MPN Assays
Most Probable Number enrichment
🦠
Biofilm Studies
Suspension and biofilm culture systems
🌱
Microbial Ecology
Environmental oligotroph recovery
Preparation (Summary)
1
Dissolve 3.12 g in 1 L of purified water. Mix with gentle agitation until fully dissolved.
2
Dispense into flasks, tubes, or containers as required.
3
Autoclave at 121°C for 15 minutes. Do not over-autoclave.
4
Cool to 20–28°C before inoculation. Inspect: clear, yellow-coloured solution expected.
Incubation & Interpretation
| Temperature | 20–28°C (environmental/water organisms); 35–37°C for faecal indicators |
| Duration | 24–72 hours for faster-growing strains; up to 7 days for field/environmental water samples |
| Positive Result | Turbidity, visible biomass, pellicle, or sediment formation |
| Negative Result | Clear broth throughout full incubation period |
| Further Testing | Plate onto R2A Agar; Gram stain; microscopy; molecular identification |
⚠️ For Laboratory Use Only. Environmental water samples and inoculated media may contain pathogenic organisms. Handle in accordance with applicable Biosafety Level (BSL) requirements. Neutralise residual chlorine in water samples with sodium thiosulfate before inoculation.
FAQs
❓ Why use a low-nutrient medium instead of a standard rich medium like TSA?
Conventional nutrient-rich media can be too concentrated for oligotrophic bacteria adapted to low-nutrient environments like treated drinking water — the osmotic shock and nutrient overload can inhibit or kill these organisms outright. R2A's dilute formulation, combined with extended incubation, allows recovery of stressed, chlorine-tolerant, and slow-growing species that rich media would miss entirely, giving a far more accurate picture of the true microbial population.
❓ Why does starch appear in the formula?
Soluble starch acts as a neutraliser, binding and neutralising toxic metabolic by-products that can otherwise inhibit stressed or injured cells during recovery — important for bacteria that have survived chlorination or other water treatment stresses.
❓ Can R2A Broth be used interchangeably with R2A Agar?
They share an identical nutrient formulation (R2A Broth omits only the agar). Broth format suits MPN assays, enrichment cultures, and suspension/biofilm work; the agar format is used for plate counts and colony isolation. Many workflows use both — broth for initial recovery/enrichment, followed by agar for enumeration and isolation.
Product Specifications
| Product Name | R2A Broth (Reasoner's 2A Broth) |
| Catalogue Number | AS-1397 |
| Format | Dehydrated powder — reconstitute as liquid broth |
| Medium Type | Low-nutrient, non-selective liquid medium |
| Final pH (prepared, 25°C) | 7.2 ± 0.2 |
| Suspension Rate | 3.12 g/L |
| Sterilisation | Autoclave at 121°C for 15 minutes. Do not over-autoclave. |
| Appearance (powder) | Cream to yellow, homogeneous, free-flowing powder |
| Appearance (prepared) | Yellow-coloured, clear solution |
Composition (per litre of prepared medium)
| Ingredient | g/L | Function |
|---|---|---|
| Proteose Peptone | 0.500 | Complex nitrogen, amino acid, and growth factor source |
| Casein Acid Hydrolysate (Casamino Acids) | 0.500 | Defined amino acid mixture; supports fastidious organisms |
| Yeast Extract | 0.500 | B-vitamins, nucleotides, and accessory growth factors |
| Dextrose (D-Glucose) | 0.500 | Readily metabolisable carbon and energy source |
| Soluble Starch | 0.500 | Neutralises toxic metabolites; mimics environmental polysaccharides |
| Dipotassium Phosphate (K₂HPO₄) | 0.300 | Phosphate buffer and essential phosphorus source |
| Sodium Pyruvate | 0.300 | Rapidly catabolised carbon source; supports stressed-cell recovery |
| Magnesium Sulphate | 0.024 | Essential magnesium cofactor; ion source |
| Purified Water | q.s. 1 L | — |
Total: 3.12 g/L | Final pH 7.2 ± 0.2 at 25°C. Formula adjusted and standardised to suit performance parameters.
Preparation Protocol
Dissolution:
Dissolve 3.12 g in 1 L of purified (Milli-Q or Type 1) water with gentle agitation at room temperature. Heat if necessary to fully dissolve. Solution should be clear.
Sterilisation:
Autoclave at 121°C for 15 minutes. Do not over-autoclave — excessive heat will caramelise carbohydrate components, causing browning and performance degradation.
Inoculation:
Cool to 20–28°C. Neutralise residual disinfectants in water samples (e.g. 0.1 mL of 3% sodium thiosulfate per 100 mL sample) before inoculation.
Performance Specifications
| Parameter | Specification | Method |
|---|---|---|
| Sterility (prepared) | No turbidity after 14 d at 28°C | USP <71> |
| Productivity — E. coli ATCC 25922 | Good–luxuriant growth, 24–72 h at 35–37°C | APHA 9215 / ISO 8245 |
| Productivity — Enterococcus faecalis ATCC 29212 | Good–luxuriant growth, 24–72 h at 35–37°C | APHA 9215 / ISO 8245 |
| Productivity — Salmonella Enteritidis ATCC 13076 | Good–luxuriant growth, 24–72 h at 35–37°C | APHA 9215 / ISO 8245 |
| Moisture Content (powder) | < 5.0% | Loss on drying, 105°C |
Key Limitations
Non-selective — strict aseptic technique is essential to avoid environmental contamination
May not support growth of copiotrophic (high-nutrient-requiring) organisms
Residual disinfectants (chlorine, chloramine) in water samples will inhibit recovery — neutralise before inoculation
Turbidity alone is not definitive; assess all visual cues and use uninoculated controls
Over-autoclaving will degrade carbohydrate components
May not support growth of copiotrophic (high-nutrient-requiring) organisms
Residual disinfectants (chlorine, chloramine) in water samples will inhibit recovery — neutralise before inoculation
Turbidity alone is not definitive; assess all visual cues and use uninoculated controls
Over-autoclaving will degrade carbohydrate components
Storage
| Dehydrated Powder | Below 30°C; dry; original tightly sealed container |
| Prepared Broth | 2–8°C; protected from light; use within 4 weeks |
| Shelf Life (powder) | As stated on label (typically 3 years from manufacture) |
Literature & References
| 1 | Reasoner DJ, Geldreich EE. A new medium for the enumeration and subculture of bacteria from potable water. Applied and Environmental Microbiology. 1985;49(1):1–7. |
| 2 | Standard Methods for the Examination of Water and Wastewater, 24th ed. APHA, AWWA, WEF. |
| 3 | ISO 8245:1999. Water quality — Guidelines for the determination of total organic carbon (TOC) and dissolved organic carbon (DOC). |
| 4 | ASTM D9217. Standard Test Method for Heterotrophic Plate Count. |
Section 1 — Identification
| Product | R2A Broth (Reasoner's 2A Broth) |
| Catalogue No. | AS-1397 |
| Recommended Use | Low-nutrient microbiological liquid medium — laboratory research only |
| Supplier | AuSaMicS Pty Ltd, 36/25 Trafalgar Road, Epping VIC 3076, Australia |
| Emergency Telephone | Poisons Information Centre: 13 11 26 (Australia, 24 hr) |
Section 2 — Hazard Identification
GHS Classification: Not classified as a hazardous substance under Australian WHS Regulations 2023 at typical laboratory quantities.
| Precautionary Statements | P260 Do not breathe dust | P264 Wash hands after handling | P270 Do not eat/drink/smoke | P501 Dispose per local regulations |
| Biological Hazard Note | Environmental water samples and inoculated media may contain pathogenic or opportunistic microorganisms. Handle all inoculated media in accordance with applicable Biosafety Level (BSL) requirements and institutional biosafety guidelines. |
First Aid, Fire, Spill, Handling & PPE (Summary)
| Topic | Key Guidance |
|---|---|
| Inhalation | Remove to fresh air. Seek medical attention if symptoms persist. |
| Skin Contact | Wash with soap and water ≥15 min. Remove contaminated clothing. |
| Eye Contact | Irrigate with water ≥15 min. Seek immediate medical attention. |
| Ingestion | Do not induce vomiting. Rinse mouth. Seek medical attention. |
| Fire | Not flammable. Use CO₂ or dry chemical powder. |
| Spill (powder) | Sweep up; avoid dust generation. Collect in sealed labelled container. |
| Spill (inoculated) | Treat as biological hazard. Decontaminate per institutional biosafety protocol. |
| PPE | Nitrile gloves, safety goggles, lab coat. Biosafety cabinet for inoculated work. |
Disposal
| Uninoculated Medium | Dispose via licensed chemical waste contractor or as general laboratory waste per local EPA regulations |
| Inoculated / Used Broth | Autoclave at 121°C for 30 minutes to inactivate biological material before disposal. Dispose of decontaminated liquid per institutional policy. |
Regulatory
| WHS Regulations 2023 | Compliant — not classified as hazardous |
| ARTG / TGA | Not registered — laboratory use only |
| Transport | Not classified as dangerous goods (ADG / IATA / IMDG) |
Quality Specifications
| Parameter | Specification | Method |
|---|---|---|
| Appearance (powder) | Cream to yellow, homogeneous, free-flowing powder | Visual inspection |
| Final pH (prepared, 25°C) | 7.2 ± 0.2 | Calibrated pH electrode |
| Appearance (prepared broth) | Yellow-coloured, clear solution | Visual inspection |
| Moisture Content (powder) | < 5.0% | Loss on drying, 105°C |
| Sterility (prepared) | No turbidity after 14 d at 28°C | USP <71> |
| Productivity — E. coli ATCC 25922 | Good–luxuriant growth, 24–72 h | APHA 9215 / ISO 8245 |
| Productivity — Enterococcus faecalis ATCC 29212 | Good–luxuriant growth, 24–72 h | APHA 9215 / ISO 8245 |
| Batch COA | Available every production lot | Included with every order |
Manufacturing & Documentation
Manufactured by AuSaMicS Pty Ltd
36/25 Trafalgar Road, Epping, VIC 3076, Australia | ABN 56 676 640 467
✓ Formulated per Reasoner & Geldreich (1985) reference composition
✓ Validated per APHA 9215, US EPA 9215, ISO 8245, ASTM D9217
✓ Batch QC — pH, sterility, moisture content, growth promotion
✓ COA, TDS, SDS included with every order
✓ Australian stock — same-week dispatch, no import delays
36/25 Trafalgar Road, Epping, VIC 3076, Australia | ABN 56 676 640 467
✓ Formulated per Reasoner & Geldreich (1985) reference composition
✓ Validated per APHA 9215, US EPA 9215, ISO 8245, ASTM D9217
✓ Batch QC — pH, sterility, moisture content, growth promotion
✓ COA, TDS, SDS included with every order
✓ Australian stock — same-week dispatch, no import delays
⚠️ For laboratory, water quality testing, and environmental research use only. Not for food, therapeutic, veterinary, or direct human use.
Batch-Specific Certificate of Analysis
Every lot ships with its own Certificate of Analysis, documenting appearance, pH, moisture content, sterility, and growth-promotion results against ATCC reference strains, before release.