Pharmacopoeial media · Clostridia · granulated
Columbia Agar – subculture of clostridia
This granulated Columbia Agar is used in the pharmacopoeial test for Clostridia: after enrichment in Reinforced Clostridial Medium, the culture is plated on Columbia Agar, with gentamicin, and incubated anaerobically.
- Granulated – less dust, better flow
- Pharmacopoeial test for Clostridia
- Anaerobic incubation
How Columbia Agar works
Several peptones, starch and yeast extract make Columbia Agar a rich base on which clostridia form colonies under anaerobic conditions. Gentamicin added after autoclaving suppresses aerobic Gram-negative bacteria.
Typical colony appearance
| Organism | Colonies |
| Clostridium sporogenes | Colourless colonies under anaerobic incubation |
Technical data
| Preparation | 44 g/L; boil with stirring to dissolve, autoclave 121 °C 15 min, cool to 45–50 °C; gentamicin (20 mg/L) can be added as required by the method |
| Final pH | 7.3 ± 0.2 |
| Incubation | 30–35 °C, anaerobic, 48 h |
| Storage | Dry, dark place; keep the container tightly closed |
| Shelf life | 3 years unopened |
Applications and practical notes
Tests for specified micro-organisms in non-sterile products, described in Ph. Eur. 2.6.13 and USP <62>, combine an enrichment in soya-bean casein digest broth with selective media for each organism and confirmation of typical colonies. Typical applications include:
- Raw materials and active ingredients
- Oral and topical non-sterile products
- Herbal products and food supplements
- Method suitability and growth promotion tests
Working with Columbia Agar: Add gentamicin after the agar has cooled to 45–50 °C, and incubate the plates anaerobically at 30–35 °C for 48 hours.
Good practice with dehydrated media: keep the bottle tightly closed in a cool, dry place, weigh the powder quickly to avoid moisture uptake, and use fresh distilled or deionised water. Check the pH of each new batch after preparation and before use, and label prepared media with the date. Performance of each lot can be verified with reference strains according to ISO 11133, the standard for the preparation, production, storage and performance testing of culture media.
About pharmacopoeial microbiological testing: the European Pharmacopoeia and the USP describe harmonised methods for non-sterile products – microbial enumeration (Ph. Eur. 2.6.12, USP <61>) and tests for specified micro-organisms (Ph. Eur. 2.6.13, USP <62>) – and the sterility test for sterile products (Ph. Eur. 2.6.1, USP <71>). The chapters define the media, incubation conditions and the growth promotion test that each batch of medium must pass with reference strains. COLO.Science offers the media, diluents, neutralisers and QC strains for these tests from one source.
Complete sets from one supplier: COLO.Science supplies culture media, supplements, rapid tests, identification kits and QC strains as complete sets for the method you follow. Send us your sample types and standards, and we will prepare an offer with the matching products and documentation.
Columbia Agar is supplied by COLO.Science in the pack sizes listed under Ordering information. For larger quantities, regular deliveries or method-specific sets that include Columbia Agar, please send us a request. With every delivery of Columbia Agar you receive the lot number and expiry date, and on request we send the available documentation for Columbia Agar.
Where Columbia Agar fits in pharmacopoeial testing
- Sample preparation – Buffered Sodium Chloride-Peptone Solution, Tryptic Soy Broth and neutralising diluents
- Microbial enumeration – Tryptic Soy Agar (TAMC) and Sabouraud Dextrose Agar (TYMC)
- Specified micro-organisms – enrichment in Tryptic Soy Broth, then MacConkey, Mannitol Salt, Cetrimide, XLD, VRBG, RCM and Columbia media
- Sterility test – Fluid Thioglycollate Medium and Tryptic Soy Broth, 14 days
See all pharmacopoeial media in the Microbiology Catalogue →
Ordering information
| Product | COLO code | Pack |
|---|---|---|
| Columbia Agar, granulated | PRO7627 | 250 g |
Product notice: preparation, storage conditions and shelf life are given on the label. Technical data on this page are for orientation; the label and the lot documentation apply. B2B prices are quoted net, excluding VAT.
Sales and technical support
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Quotations and technical support for culture media and microbiology products across our international sales territory. B2B prices are net, excluding VAT.
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Need the complete set for your method?
Send the sample type, target organism and the standard you follow. COLO.Science will put together the media, supplements, QC strains and confirmation tests for the whole procedure.
