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R2A Agar (R2-A Agar) | Ph. Eur. Medium S Culture Medium | Water Testing Media | Ausamics
$29.00 AUD
Dehydrated Culture Medium · Water Microbiology
R2A Agar
Reasoner's 2A — ISO 6222 · Ph. Eur. Medium S · Standard Methods 9215 B
ISO 6222:1999
Ph. Eur. 11th Ed.
APHA/AWWA SM-9215B
Drinking Water Certified
AuSaMicS
Life Science™
Cat No.
AS-1337
CAS No.
—
Format
Dehydrated Powder
Yield (1 L)
≈ 55 plates
Final pH
7.2 ± 0.2
Overview
R2A Agar (Reasoner's 2A) is the internationally mandated low-nutrient solid medium for the enumeration of heterotrophic bacteria in treated drinking water, bottled water, swimming-pool water, dialysis water, and other purified waters. Its deliberately oligotrophic formulation — featuring nine carefully balanced components at very low concentrations — replicates the nutrient-depleted environment of treated water systems and allows the recovery of slow-growing, chlorine-stressed, and otherwise fastidious water bacteria that are undetectable on richer media such as PCA.
Sodium pyruvate and soluble starch act synergistically to neutralise peroxides and reactive oxygen species generated during sample processing, dramatically improving the recovery of sub-lethally injured organisms. K₂HPO₄ provides pH buffering; MgSO₄ supplies essential divalent cations for enzyme function and membrane integrity. The combination of low nutrients, long incubation (5–7 days), and reduced temperature (20–28 °C) yields colony counts up to 100× higher than conventional Plate Count Agar.
Regulatory Status & Applications
Drinking & Bottled Water
Mandatory under ISO 6222:1999 and Ph. Eur. 2.6.12 (Medium S).
Official method for EU Directive compliance and IBWA bottle water testing.
Pharmaceutical & Dialysis Water
Required for pharmacopoeial water testing (WFI, PW).
Recognised in Ph. Eur. 11th Ed. and USP <1231> guidelines.
Research & Environmental
Selective recovery of oligotrophic genera: Pseudomonas,
Sphingomonas, Flavobacterium, Acinetobacter.
Pool water, dental-unit waterlines, and environmental monitoring.
Key Features
| Nutrient Level | Very low — simulates oligotrophic (nutrient-depleted) environments |
| Recovery Advantage | Up to 100× higher counts vs. Plate Count Agar for water isolates |
| Injured Cell Recovery | Starch + pyruvate neutralise peroxides; rescues chlorine-damaged cells |
| Colony Morphology | Clear, distinct colonies — easy visual counting at all incubation temperatures |
| Regulatory Compliance | ISO 6222:1999 · Ph. Eur. 2.6.12 Medium S · APHA SM-9215B · EPA 1604 |
| Counting Rule | Count ALL visible colonies regardless of size, colour, or morphology |
Incubation Conditions
Standard (ISO / Ph. Eur.)
20–28 °C
5–7 days · Maximum colony recovery
Accelerated (when required)
35–37 °C
44–72 hours · Faster results
Genus Targets
R2A Agar supports recovery of heterotrophic bacteria commonly found in treated water systems, including but not limited to: Pseudomonas, Sphingomonas, Flavobacterium, Acinetobacter, Burkholderia, Caulobacter, Methylobacterium, and Brevundimonas spp. These organisms are frequently oligotrophic, slow-growing, and unable to form visible colonies on richer media within standard incubation periods.
Storage & Shelf Life
| Dehydrated Powder | 15–25 °C, dry place, tightly closed container, away from light |
| Prepared Plates | 2–8 °C, sealed in plastic bag, use within 4 weeks of preparation |
| After Opening | Reseal immediately; use desiccant if ambient humidity > 60% RH |
Original Reference: Reasoner D.J. & Geldreich E.E. (1985). A new medium for the
enumeration and subculture of bacteria from potable water. Appl. Environ. Microbiol. 49(1):1–7.
Standardised in ISO 6222:1999 and Ph. Eur. 11th Edition, Medium S.
AuSaMicS Pty Ltd (ABN 56 676 640 467) warrants that this product meets stated specifications
at time of manufacture and release. This product is intended for laboratory and research use only.
AuSaMicS Pty Ltd shall not be held liable for any direct, indirect, incidental, or consequential
damages resulting from use outside the intended application. By using this product, the purchaser
accepts these terms. · 31 Longview CT, Thomastown VIC 3074, Australia ·
support@ausamics.com · +61 412 520 598 · www.ausamics.com.au
Product Identification
| Product Name | R2A Agar (Reasoner's 2A) |
| Synonyms | R2A Medium; ISO 6222 Medium; Ph. Eur. Medium S |
| Catalog No. | AS-1337 |
| Format | Dehydrated powder, pale cream to light beige |
| Grade | Microbiological / Analytical Grade |
| Lot No. | See label |
| Retest Date | See label |
Physical Properties
| Appearance | Homogeneous free-flowing powder |
| Colour | Pale cream to light beige |
| Odour | Faint, characteristic (peptone/yeast) |
| Solubility (1 L) | 18.12 g in purified water; dissolves on heating |
| pH (prepared) | 7.2 ± 0.2 at 25 °C |
| Agar Gel Point | ≈ 32–34 °C (gel), ≈ 84–86 °C (melt) |
| Prepared Medium | Clear to very slightly opalescent gel, light amber |
Composition (per litre — ISO 6222 / Ph. Eur. Standard)
| Component | Role / Function | Amount (g/L) |
|---|---|---|
| Yeast Extract | Vitamins, amino acids — primary carbon/nitrogen source | 0.50 |
| Proteose Peptone No. 3 (or Polypeptone) | Peptides, nitrogen — slow-release nutrient | 0.50 |
| Casein Hydrolysate (acid) | Amino acids — supplementary nitrogen source | 0.50 |
| Glucose (Dextrose) | Fermentable carbon source — readily metabolised | 0.50 |
| Starch (Soluble) | Carbon source + peroxide neutralisation — protects injured cells | 0.50 |
| K₂HPO₄ (Dipotassium Hydrogen Phosphate) | pH buffer — stabilises at 7.2 | 0.30 |
| MgSO₄ · 7H₂O (Magnesium Sulphate) | Divalent cation — enzyme cofactor, membrane integrity | 0.024 |
| Sodium Pyruvate | Peroxide scavenger — rescues chlorine-injured cells | 0.30 |
| Agar (bacteriological grade) | Solidifying agent | 15.00 |
| Total dehydrated weight to suspend per litre | 18.12 g/L | |
Preparation Protocol
- 1Weigh 18.12 g of dehydrated R2A Agar and suspend in 1 L of purified/distilled water (type 1 or equivalent).
- 2Heat with frequent agitation on a hot plate or water bath. Bring to a full boil for 1 minute until completely dissolved.
- 3Autoclave at 121 °C (15 psi) for 15 minutes. Do not over-autoclave; excessive heating degrades pyruvate and starch.
- 4Cool in a 45–50 °C water bath. Pour 15–20 mL per 90 mm Petri dish under sterile conditions.
- 5Allow plates to solidify on a level surface. Dry at 37 °C for 30–45 min (or RT overnight) before use.
Incubation & Counting
Standard — ISO 6222 / Ph. Eur.
20–28 °C
Incubate 5–7 days. Count ALL visible colonies.
Accelerated (where specified)
35–37 °C
Incubate 44–72 hours. Count ALL visible colonies.
Count all visible colonies regardless of size, colour, or morphology. Report as CFU/mL.
Do not use for coliform enumeration — R2A Agar is non-selective for coliforms.
Quality Specifications
| Appearance (powder) | Homogeneous; no lumps or colour change |
| pH (prepared, 25 °C) | 7.0 – 7.4 |
| Growth Promotion | Pseudomonas aeruginosa ATCC 9027 — good growth |
| Growth Promotion | Staphylococcus aureus ATCC 6538 — good growth |
| Inhibition Test | Not applicable (non-selective medium) |
| Sterility | Prepared medium negative after 14-day incubation at 30–35 °C |
Technical References
| Primary Reference | Reasoner & Geldreich (1985). Appl. Environ. Microbiol. 49(1):1–7 |
| ISO Standard | ISO 6222:1999 — Water quality: Enumeration of culturable micro-organisms |
| Pharmacopoeial | Ph. Eur. 11th Ed. 2.6.12 — Microbiological Examination of Non-Sterile Products (Medium S) |
| APHA/AWWA | Standard Methods for Examination of Water & Wastewater, 9215 B |
| US EPA | EPA Method 1604 (selected applications) |
AuSaMicS Pty Ltd (ABN 56 676 640 467) · 31 Longview CT, Thomastown VIC 3074, Australia ·
support@ausamics.com · +61 412 520 598 · www.ausamics.com.au
This Technical Data Sheet is provided for informational purposes only. Specifications are subject to change without notice. For the most current version visit www.ausamics.com.au.
This Technical Data Sheet is provided for informational purposes only. Specifications are subject to change without notice. For the most current version visit www.ausamics.com.au.
Safety Data Sheet — GHS Format (Australian WHS Regulations)
This SDS is prepared in accordance with the Work Health and Safety (WHS) Regulations and the Globally Harmonised System of Classification and Labelling of Chemicals (GHS), 7th Revision.
This SDS is prepared in accordance with the Work Health and Safety (WHS) Regulations and the Globally Harmonised System of Classification and Labelling of Chemicals (GHS), 7th Revision.
Section 1 — Identification
| Product Name | R2A Agar |
| Other Names | Reasoner's 2A Agar; ISO 6222 Medium; Ph. Eur. Medium S |
| Catalog No. | AS-1337 |
| Intended Use | Microbiological culture medium for laboratory use only |
| Supplier | AuSaMicS Pty Ltd, 31 Longview CT, Thomastown VIC 3074, Australia |
| Phone | +61 412 520 598 |
| support@ausamics.com | |
| Emergency | Poisons Information Centre: 13 11 26 (Australia, 24 h) |
Section 2 — Hazard Identification
| GHS Classification | Not classified as hazardous under GHS/WHS Regulations |
| Signal Word | None required |
| Hazard Statements | None allocated |
| Precautionary Statements | P260, P262, P264, P270, P272, P501 |
No GHS pictograms required. Product is not classified as dangerous goods for transport.
Section 3 — Composition / Information on Ingredients
| Component | CAS No. | Proportion (w/w) | Classification |
|---|---|---|---|
| Agar (bacteriological) | 9002-18-0 | ~82.8% | Not classified |
| Yeast Extract | 8013-01-2 | ~2.8% | Not classified |
| Proteose Peptone No. 3 | — | ~2.8% | Not classified |
| Casein Hydrolysate | 65072-00-6 | ~2.8% | Not classified |
| Glucose (Dextrose) | 50-99-7 | ~2.8% | Not classified |
| Starch (Soluble) | 9005-84-9 | ~2.8% | Not classified |
| K₂HPO₄ | 7758-11-4 | ~1.7% | Not classified |
| Sodium Pyruvate | 113-24-6 | ~1.7% | Not classified |
| MgSO₄ · 7H₂O | 10034-99-8 | ~0.1% | Not classified |
Section 4 — First Aid Measures
| Inhalation | Remove to fresh air. If symptoms persist, seek medical advice. |
| Skin Contact | Wash with soap and water. Remove contaminated clothing. No special treatment required. |
| Eye Contact | Rinse with copious water for 15 min, holding eyelids open. Seek medical advice if irritation persists. |
| Ingestion | Do not induce vomiting. Rinse mouth with water. Seek medical advice. Product has low acute toxicity. |
| Medical Note | No specific antidote. Treat symptomatically. |
Section 5 — Fire-Fighting Measures
| Flash Point | Not applicable (non-flammable powder) |
| Extinguishing Media | CO₂, dry powder, or water spray suitable for surrounding fire |
| Special Hazards | None known; agar and organic components may smoulder |
| Protective Equipment | Self-contained breathing apparatus (SCBA) in enclosed spaces |
Section 6 — Accidental Release Measures
Personal precautions: Avoid dust generation. Use appropriate PPE (gloves, dust mask). Ventilate area. Environmental precautions: Prevent entry into drains, waterways, or soil. Clean-up: Collect dry powder with vacuum or damp cloth. Avoid dry sweeping (dust hazard). Dispose per Section 13.
Section 7 — Handling and Storage
| Handling | Handle in well-ventilated area. Avoid dust inhalation. Use standard lab PPE. Do not eat or drink during use. |
| Storage (dehydrated) | 15–25 °C, dry, away from direct sunlight, tightly closed container |
| Prepared medium | 2–8 °C, sealed, use within 4 weeks |
| Incompatibilities | Strong oxidising agents; strong acids/bases |
Section 8 — Exposure Controls / Personal Protection
| OEL / TWA | No specific WES established (Safe Work Australia) |
| Engineering Controls | Local exhaust ventilation where dust generation is possible |
| Respiratory | P2 dust mask if generating significant dust |
| Hand Protection | Nitrile or latex gloves (EN 374 / AS/NZS 2161) |
| Eye Protection | Safety glasses with side shields |
| Body Protection | Standard lab coat and closed footwear |
Section 9 — Physical and Chemical Properties
| Physical State | Solid (powder) |
| Colour | Pale cream to light beige |
| Odour | Faint, characteristic |
| Odour Threshold | Not determined |
| pH (prepared, 25 °C) | 7.2 ± 0.2 |
| Melting Point | ~84–86 °C (agar melt) |
| Boiling Point | Not applicable |
| Flash Point | Not applicable |
| Solubility | 18.12 g/L on heating; swells in cold water |
| Vapour Pressure | Negligible |
Section 10 — Stability and Reactivity
| Stability | Stable under recommended storage conditions |
| Conditions to Avoid | Moisture, heat above 40 °C, direct sunlight |
| Hazardous Decomposition | CO, CO₂, and nitrogen oxides possible at very high temperatures |
| Polymerisation | Will not occur |
Section 11 — Toxicological Information
| Acute Oral Toxicity | Low — components are food-grade or generally regarded as safe (GRAS) |
| Skin Irritation | Not expected to be irritating |
| Eye Irritation | Dust may cause mild mechanical irritation |
| Sensitisation | No known sensitisation effects |
| Carcinogenicity | Not classified (IARC, NTP) |
| Reproductive Toxicity | Not classified |
| STOT (single/repeat) | Not classified |
Section 12 — Ecological Information
| Aquatic Toxicity | Not expected to be harmful at typical spill concentrations |
| Persistence | Components are biodegradable |
| Bioaccumulation | Not expected |
| Soil Mobility | Low (agar immobilises on contact with soil) |
Section 13 — Disposal Considerations
Dispose of unused product and contaminated materials in accordance with local, state, and federal regulations. Autoclave or chemically inactivate any prepared medium that has been used for culturing micro-organisms before disposal. Contact a licensed waste contractor for large quantities. Do not discharge prepared medium to drains without decontamination.
Section 14 — Transport Information
| UN Number | Not regulated |
| ADG (Australia) | Not classified as dangerous goods |
| IATA / ICAO | Not restricted |
| IMDG | Not classified |
Section 15 — Regulatory Information
| AICS (Australia) | All components listed on AICS (Australian Inventory of Chemical Substances) |
| SUSMP (Poisons Schedule) | Not scheduled |
| WHS Regulations | Not classified as a hazardous chemical under WHS Regulations 2017 |
| REACH (EU) | Components comply with REACH Regulation (EC) No. 1907/2006 |
Section 16 — Other Information
| SDS Prepared By | AuSaMicS Pty Ltd — Technical & Quality Department |
| Issue Date | March 2026 |
| Revision No. | 1.0 |
| Supersedes | — |
| Disclaimer | Information is based on current knowledge and believed to be correct. It does not constitute a guarantee of any specific product quality parameters. |
AuSaMicS Pty Ltd (ABN 56 676 640 467) · 31 Longview CT, Thomastown VIC 3074, Australia ·
support@ausamics.com · +61 412 520 598 · www.ausamics.com.au
This SDS is prepared in accordance with Australian WHS Regulations and GHS (7th Rev.). For laboratory use only. Not for human, veterinary, food, feed, or pharmaceutical use.
This SDS is prepared in accordance with Australian WHS Regulations and GHS (7th Rev.). For laboratory use only. Not for human, veterinary, food, feed, or pharmaceutical use.
Product Details
| Product Name | R2A Agar |
| Catalog No. | AS-1337 |
| Lot No. | R2A260301 |
| Manufacturing Date | March 2026 |
| Retest Date | March 2028 |
| Grade | Microbiological / Analytical |
| Standard Compliance | ISO 6222:1999 · Ph. Eur. 11th Ed. |
Document Info
| COA No. | COA-AS-1337-L001 |
| Issue Date | March 2026 |
| Issued By | AuSaMicS Quality Control |
| Test Method Ref. | ISO 6222 · Ph. Eur. 2.6.12 |
Test Results
| Test Parameter | Specification | Method | Result | Status |
|---|---|---|---|---|
| Appearance (powder) | Homogeneous, free-flowing powder; cream to light beige | Visual | Conforms | PASS |
| Colour (prepared medium) | Clear to slightly opalescent; light amber | Visual | Conforms | PASS |
| pH (prepared, 25 °C) | 7.0 – 7.4 | Potentiometry (ISO 10523) | 7.2 | PASS |
| Gel Strength (prepared) | Firm, clear gel; no syneresis | Visual — plate inspection | Firm, clear | PASS |
| Loss on Drying | ≤ 7.0% w/w | 105 °C / 2 h (gravimetric) | 3.8% | PASS |
| Solubility | Complete dissolution at boiling (18.12 g/L) | Suspension + heating | Complete | PASS |
| Growth Promotion — Pseudomonas aeruginosa ATCC 9027 | Recovery ≥ 70% vs. reference medium; good growth | ISO 6222 growth promotion | Recovery 94% | PASS |
| Growth Promotion — Staphylococcus aureus ATCC 6538 | Recovery ≥ 70% vs. reference medium; good growth | ISO 6222 growth promotion | Recovery 89% | PASS |
| Growth Promotion — Micrococcus luteus ATCC 9341 | Good growth; visible colonies at 48 h (28 °C) | Ph. Eur. 2.6.12 growth test | Good growth | PASS |
| Sterility (prepared medium) | No growth at 14 days (30–35 °C) | Incubation sterility check | No growth | PASS |
| Homogeneity (powder) | No clumping; uniform particle distribution | Visual / sieve test | Uniform | PASS |
| ISO 6222 Compliance | Full conformance with ISO 6222:1999 formula and performance criteria | Compositional + performance review | Conforms | CONFORM |
Conclusion: Lot R2A260301 has been tested against all specifications and fully
meets the requirements of ISO 6222:1999 and Ph. Eur. 11th Edition Medium S.
This lot is RELEASED for use.
Quality Control Analyst
AuSaMicS Quality Control Department
Date: March 2026 | Signature: _______________
Quality Manager
AuSaMicS Pty Ltd
Date: March 2026 | Signature: _______________
AuSaMicS Pty Ltd (ABN 56 676 640 467) warrants that this product meets the specifications
stated in this Certificate of Analysis at the time of manufacture and release.
This product is for laboratory and research use only. AuSaMicS Pty Ltd shall not be held liable for
any direct, indirect, incidental, or consequential damages resulting from use outside its intended application.
By using this product the purchaser agrees to these terms. ·
31 Longview CT, Thomastown VIC 3074, Australia · support@ausamics.com · +61 412 520 598 · www.ausamics.com.au