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AS-1212
Dichloran Rose Bengal Chloramphenicol Agar (DRBC) – Selective Medium for Yeasts & Moulds AS-1212
$45.00
AUD ex GST
DRBC AGAR
Catalogue No. AS-1212
www.ausamics.com.au
AS-1212 Selective Yeasts & Moulds ISO 21527-1 FDA-BAM M183
Dichloran-Rose Bengal Chloramphenicol Agar (DRBC)
Selective medium for the enumeration of yeasts and moulds in food, feed, and environmental samples
DRBC Agar is a selective solid culture medium designed for the isolation and enumeration of yeasts and moulds, particularly from food and environmental samples. It is a modification of Rose Bengal Chloramphenicol Agar (RBC) containing dichloran, which restricts the radial growth of rapidly spreading moulds, allowing improved colony separation and accurate counting in mixed fungal populations.
AuSaMicS manufactures DRBC Agar in Melbourne, Australia, to the composition and performance criteria of ISO 21527-1 and FDA-BAM M183, giving reliable colony morphology and lot-to-lot reproducibility for routine food microbiology and quality control testing.
Performance Snapshot
Final pH5.6 ± 0.2
Incubation25°C, 5 days
Appearance (powder)Pink, free-flowing
Light sensitivityYes — store dark
Shelf life (powder)24 months
Formulation completeness note: the composition of DRBC Agar is fixed by ISO 21527-1 and the original King, Hocking & Pitt (1979) formulation. The full per-litre quantities below are cross-checked against Merck GranuCult, HiMedia, and FDA-BAM M183 technical documentation, all of which agree on the same values.
Testing Workflow
1
SampleFood, feed, or environmental sample
2
DilutePrepare decimal dilutions
3
Spread Plate0.1 mL onto DRBC surface
4
Incubate25°C, dark, up to 5 days
5
CountRead at day 3 and day 5
Principle of the Medium
Functional Components
Peptone supplies nitrogen and growth factors. Glucose (dextrose) is the primary carbon and energy source. Rose Bengal partially inhibits bacterial growth and restricts fungal colony size — but is light-sensitive and photo-oxidises to compounds toxic to fungi, which is why plates must be protected from light. Dichloran further limits the excessive spreading of fast-growing moulds such as Rhizopus and Mucor, keeping colonies compact for accurate counting. Chloramphenicol, a heat-stable broad-spectrum antibiotic, suppresses bacterial contamination. Potassium phosphate provides buffering, and magnesium sulfate supplies essential ions for fungal metabolism.
Why the Lower pH
The slightly acidic pH (5.6 ± 0.2) is itself a selective feature: it favours fungal growth while inhibiting many bacteria, working alongside chloramphenicol for a compounding suppression effect on bacterial contamination — this is the key modification that distinguishes DRBC from the original Rose Bengal Chloramphenicol Agar (pH 7.2).
Key Applications
Food & Beverage Microbiology
Enumeration of yeasts and moulds in dairy products, cereals, spices, fruits, and processed foods.
Environmental & Industrial Testing
Monitoring fungal contamination in raw materials and food production/storage environments.
Regulatory Compliance Testing
Yeast and mould counts per ISO 21527-1 for products with water activity (aw) greater than 0.95.
Shelf-Life & Spoilage Studies
Tracking fungal spoilage organisms in stored or packaged food products.
Formulation & Specifications
| Component | g/L |
|---|---|
| Peptone | 5.0 |
| Glucose (Dextrose) | 10.0 |
| Potassium Dihydrogen Phosphate (KH₂PO₄) | 1.0 |
| Magnesium Sulfate (MgSO₄·7H₂O) | 0.5 |
| Rose Bengal | 0.025 |
| Dichloran | 0.002 |
| Chloramphenicol | 0.1 |
| Agar | 15.0 |
| Total | 31.627 g/L |
Technical Specifications
| Catalogue No. | AS-1212 |
| Final pH | 5.6 ± 0.2 @ 25°C |
| Appearance (powder) | Pink, free-flowing |
| Appearance (prepared) | Pink-coloured gel |
| Storage (powder) | 15–30°C, dry, dark |
| Storage (plates) | 2–8°C, protected from light |
Laboratory Preparation
1
Suspend 31.63 g of dehydrated medium in 1 L purified water.
2
Heat with agitation until completely dissolved.
3
Sterilise by autoclaving at 121°C for 15 minutes.
4
Cool to 45–50°C and pour into sterile Petri dishes.
5
Store poured plates protected from light until use.
Light Sensitivity — Handling Note
- Rose Bengal photo-oxidises under light exposure to form compounds toxic to fungi — this would suppress the very organisms the medium is designed to recover.
- Store dehydrated powder, prepared plates, and incubating plates in the dark or subdued light at every stage.
- Do not leave poured plates on an open bench under laboratory lighting for extended periods before use.
Limitations & Technical Considerations
- Light exposure degrades performance — the most common cause of reduced fungal recovery is inadequate protection from light at any stage.
- Not intended for mould spore-only enumeration — the medium enumerates viable, growing yeasts and moulds, per its ISO 21527-1 scope.
- Restricted to samples with water activity (aw) above 0.95 — per ISO 21527-1 scope; low-moisture foods may require a different method (e.g., ISO 21527-2 for aw ≤ 0.95).
- Spreading organisms can still occur — some highly mucoraceous fungi may still spread despite dichloran; use as directed and interpret atypical growth cautiously.
Cross-Reference / Equivalent Products
| Brand | Equivalent Product | Catalogue No. |
|---|---|---|
| BD Difco | DRBC Agar | 258710 |
| Oxoid (Thermo Scientific) | Dichloran Rose-Bengal Chloramphenicol Agar Base | CM0727 |
| Merck / Sigma-Aldrich | GranuCult DRBC Agar | 1.00466 (100466) |
| HiMedia | DRBC Agar | M1881 |
| AuSaMicS | DRBC Agar | AS-1212 |
Frequently Asked Questions
What is DRBC Agar used for?
It isolates and enumerates yeasts and moulds in food, feed, and environmental samples with water activity above 0.95, per ISO 21527-1 and FDA-BAM M183.
Why does DRBC Agar contain dichloran?
Dichloran restricts the radial growth of fast-spreading moulds such as Rhizopus and Mucor, keeping colonies compact and separated so they can be accurately counted rather than overgrowing the plate.
Why is DRBC Agar light-sensitive?
Rose Bengal in the medium photo-oxidises under light exposure to form compounds toxic to fungi. Plates should be stored and incubated in the dark or subdued light.
What is the difference between DRBC and RBC (Rose Bengal Chloramphenicol) Agar?
DRBC adds dichloran, halves the Rose Bengal concentration, and lowers the pH to 5.6 compared to RBC (pH 7.2) — resulting in better control of spreading moulds and increased inhibition of bacteria and yeasts.
What incubation conditions does DRBC Agar require?
Standard practice is 25°C for 5 days, with an interim read at day 3 and a final count at day 5, in a dark or subdued-light environment.
Common Search Queries This Product Answers
Researchers and procurement teams typically find this page searching for:
- "DRBC agar composition" / "Dichloran Rose Bengal Chloramphenicol Agar formula"
- "ISO 21527-1 yeast mould enumeration medium"
- "DRBC vs Rose Bengal Chloramphenicol Agar"
- "FDA BAM M183 agar"
- "buy DRBC agar Australia Melbourne"
- "selective medium for fungal food spoilage"
Technical Data Sheet
| Product Name | Dichloran-Rose Bengal Chloramphenicol Agar (DRBC) |
| Catalogue Number | AS-1212 |
| Format | Dehydrated powder |
| Manufacturer | AuSaMicS Pty Ltd, Melbourne, Australia |
Intended Use
Selective medium for the isolation and enumeration of yeasts and moulds in food, feed, and environmental samples with water activity (aw) greater than 0.95, per ISO 21527-1 and FDA-BAM M183.
Mode of Action
Peptone and glucose support fungal growth. Rose Bengal and the reduced pH (5.6) inhibit bacterial growth and restrict fungal colony size. Dichloran further limits radial spreading of fast-growing moulds. Chloramphenicol, a heat-stable antibiotic, provides broad-spectrum bacterial suppression. Together these components allow accurate enumeration of yeasts and moulds in mixed microbial populations.
Formulation (per litre)
| Ingredient | Quantity | Function |
|---|---|---|
| Peptone | 5.0 g | Nitrogen and growth factor source |
| Glucose (Dextrose) | 10.0 g | Primary carbon and energy source |
| Potassium Dihydrogen Phosphate (KH2PO4) | 1.0 g | Buffering system |
| Magnesium Sulfate (MgSO4.7H2O) | 0.5 g | Essential ions for fungal metabolism |
| Rose Bengal | 0.025 g | Partial bacterial inhibition; restricts fungal colony size |
| Dichloran | 0.002 g | Limits spreading of fast-growing moulds |
| Chloramphenicol | 0.1 g | Broad-spectrum bacterial inhibition |
| Agar | 15.0 g | Solidifying agent |
Final pH: 5.6 ± 0.2 at 25°C. Total: 31.627 g/L.
Rose Bengal photo-oxidises under light exposure to form compounds toxic to fungi. Store dehydrated medium, prepared plates, and incubating cultures protected from light at every stage.
Preparation
Suspend 31.63 g of dehydrated medium in 1 L purified water. Heat with agitation until completely dissolved. Autoclave at 121°C for 15 minutes. Cool to 45–50°C and pour into sterile Petri dishes, protected from light.
Incubation Conditions
| Parameter | Condition |
|---|---|
| Temperature | 25°C |
| Time | Up to 5 days; interim read at day 3 |
| Light | Dark or subdued light throughout |
Storage & Shelf Life
| Dehydrated medium | 15–30°C, dry, tightly sealed, protected from light — 24 months |
| Prepared plates | 2–8°C, protected from light |
Do not use if contamination, dehydration, or colour change is observed.
Literature & References
- King, A.D., Hocking, A.D., Pitt, J.I. (1979). Dichloran-rosebengal medium for enumeration and isolation of moulds from foods. Applied and Environmental Microbiology, 37(5), 959–964.
- ISO 21527-1:2008. Microbiology of food and animal feeding stuffs — Horizontal method for the enumeration of yeasts and moulds — Part 1: Colony count technique in products with water activity greater than 0.95.
- U.S. Food and Drug Administration. Bacteriological Analytical Manual (BAM), Media M183: Dichloran Rose Bengal Chloramphenicol (DRBC) Agar.
For laboratory use only. Not intended for medical, veterinary, or food consumption. Refer to the Safety Data Sheet (SDS) before use. AuSaMicS Pty Ltd accepts no liability for results obtained outside the stated preparation and storage conditions.
Safety Data Sheet — Summary
This is a summary view. The full 16-section GHS-compliant Safety Data Sheet (Australian format) is provided as a downloadable Word document alongside this page.
| Product Name | DRBC Agar, AS-1212 |
| Recommended Use | Laboratory culture medium (dehydrated) |
| Manufacturer | AuSaMicS Pty Ltd, Melbourne, Victoria, Australia |
| GHS Classification | Contains chloramphenicol — see Section 2 of full SDS |
| Signal Word | Warning |
Hazard Summary
The dehydrated medium contains chloramphenicol, an antibiotic with known potential for serious blood disorders (aplastic anaemia) with repeated or prolonged exposure. Avoid generating and inhaling dust. May cause mechanical irritation to eyes and respiratory tract. Full precautions are detailed in the complete SDS.
First Aid
| Route | Response |
|---|---|
| Inhalation | Move to fresh air. Seek medical attention if irritation persists or if a significant dust exposure occurred. |
| Skin Contact | Wash with soap and water. |
| Eye Contact | Rinse thoroughly with water for several minutes. Seek medical advice if irritation persists. |
| Ingestion | Rinse mouth. Seek medical advice. |
Full SDS (16 GHS sections, chloramphenicol hazard details, handling, disposal, transport and regulatory information) is provided as a separate Word document — see downloads.
Certificate of Analysis — Sample Format
Each batch is supplied with a lot-specific Certificate of Analysis. A representative COA is provided as a downloadable Word document; the batch-specific COA accompanies your shipment.
| Product Name | DRBC Agar |
| Catalogue Number | AS-1212 |
| Batch/Lot Number | Assigned per production batch |
| Manufacture Date | Assigned per production batch |
| Retest / Expiry Date | 24 months from manufacture |
Quality Control Results (Representative)
| Test | Specification | Result |
|---|---|---|
| Appearance (powder) | Pink, free-flowing | Conforms |
| Final pH (25°C) | 5.6 ± 0.2 | Conforms |
| Gel firmness | Firm, pink-coloured gel | Conforms |
| Aspergillus niger ATCC 16404 recovery | Good growth, restricted colony diameter | Conforms |
| Saccharomyces cerevisiae ATCC 9763 recovery | Good growth | Conforms |
| Escherichia coli ATCC 25922 (inhibition control) | Inhibited / no growth | Conforms |
| Sterility (uninoculated control) | No growth | Conforms |
This tab shows a representative format. The lot-specific Certificate of Analysis issued with your order carries the actual batch number, manufacture/expiry dates, and signed QC results.
The information provided is accurate to the best of AuSaMicS Pty Ltd's knowledge at the time of publication. Product specifications may be updated without notice. For laboratory use only — not intended for medical, veterinary, or food consumption. Users should verify suitability for their specific application prior to use.