Reinforced Clostridial Agar
Also known as：RCA · Reinforced Clostridial Medium (Solid) · Reinforced Medium for Clostridia · Reinforced Clostridial Medium Agar · Hirsch and Grinsted Agar
For the cultivation, isolation, and enumeration of Clostridium species and other anaerobic organisms.
- Category
- Dehydrated Culture Media
- Dissolve per litre
- 51 g
- Pack sizes
- 500 g · 5 kg · 25 kg
- Certifications
- ISO 22000 · Halal
Data updated：2026-11-06
- Allergens
- Soy, Milk
Overview
Reinforced Clostridial Agar (RCA) is a medium for cultivating and counting clostridia and other anaerobes. Several nitrogen sources and glucose provide rich nutrition, cysteine lowers the redox potential, and starch with sodium acetate supports growth, for counting Clostridium perfringens, C. botulinum and other anaerobes in food and bifidobacteria in probiotic products.
Principle
Reinforced Clostridial Agar is the solid form of the medium described by Hirsch and Grinsted for the cultivation and enumeration of clostridia and other anaerobic spore-formers.¹ Beef extract, peptone, and yeast extract supply nitrogen, amino acids, vitamins, and growth factors, allowing growth to be initiated from a small inoculum. Dextrose serves as the carbon and energy source, sodium chloride maintains the osmotic equilibrium, and sodium acetate buffers the medium against acids produced during fermentation. Soluble starch absorbs toxic metabolites, and L-cysteine hydrochloride lowers the redox potential to the level required by strict anaerobes. The solid medium allows the isolation of individual colonies and the enumeration of clostridia by pour-plate or surface-plating techniques under anaerobic conditions.²
Media for anaerobes and fastidious organisms
Anaerobes and fastidious organisms require media containing reducing agents, blood, or infusion components, together with an anaerobic incubation environment. Some formulations need heat-labile supplements such as blood, serum, or antibiotics added after sterilisation; follow the preparation instructions for the timing and method.
Directions
Suspend 51 g of powder in 1 L of purified water. Heat with continuous stirring and bring to the boil for 1 minute. Sterilize by autoclaving at 121°C for 15 minutes. Avoid overheating. Cool to 45-50°C. Mix well and pour into sterile Petri plates, using the plates freshly prepared or pre-reduced before inoculation. Test the finished medium for performance using stable, standard control cultures.
Cultural response
| Test organism | ATCC | Growth |
|---|---|---|
| Clostridium sporogenes | 19404 | good-luxuriant |
| Clostridium perfringens | 13124 | good-luxuriant |
Product highlights
- Food-grade raw materials, produced in an ISO 22000 certified facility
- Halal certified, suitable for the Malaysian, Indonesian, and Middle Eastern markets
- Manufactured to the standard formulation, 51 g per litre
- Performance verified against standard control strains before release (Clostridium sporogenes, Clostridium perfringens)
- Available in 500 g / 5 kg / 25 kg, from laboratory to industrial scale
- COA, specification sheet, and technical data sheet available; samples on request
- Manufactured in Taiwan with reliable supply
Food grade versus laboratory grade
Most culture media suppliers use laboratory-grade raw materials, which are held to lower standards for heavy metal residues, microbial contamination control, and traceability. That is adequate for pure research but not for applications with stricter raw-material requirements. STBIO manufactures with food-grade raw materials throughout, in a facility certified to ISO 22000 food safety management.
- Food microbiology laboratories working to ISO 17025 or equivalent requirements
- Biotech manufacturers exporting fermentation products and needing full raw-material traceability
- Organisations with ESG or compliance audit requirements across their supply chain
- Companies sourcing both Halal and non-Halal products who need one consistent material grade
Frequently asked questions
01How much powder per litre?
Use 51 g per litre of deionised water; preparation and sterilisation conditions are given on the specification sheet.
02Which organisms is it suitable for?
Anaerobes, Spore formers, Gram-positive, C. perfringens, C. botulinum, C. butyricum, Clostridium sporogenes, Clostridium perfringens. See the cultural response table and the specification sheet.
03Can it be used for food-grade applications?
Yes. It is made from food-grade raw materials in an ISO 22000 certified facility and is suitable for culturing starters for fermented products that are consumed directly.
04How is this product prepared?
Suspend 51 g of powder in 1 L of purified water. Heat with continuous stirring and bring to the boil for 1 minute. Sterilize by autoclaving at 121°C for 15 minutes. Avoid overheating. Cool to 45-50°C. Mix well and pour into sterile Petri plates, using the plates freshly prepared or pre-reduced before inoculation. Test the finished medium for performance using stable, standard control cultures.
05How do I request a bulk quotation, and can you provide a COA?
Yes. This product is available in 500 g, 5 kg, 25 kg. Tell us your application and volume when requesting a quotation; we reply within one working day and can supply the COA, specification sheet, and technical data sheet.
References
- 1. Hirsch A. and Grinsted E., 1954. Methods for the growth and enumeration of anaerobic spore-formers from cheese, with observations on the effect of nisin. J. Dairy Res., 21:101-110.
- 2. Atlas R. M., 2010. Handbook of Microbiological Media, 4th Ed., CRC Press, Boca Raton.