Robinson's Cooked Meat Medium (R.C Medium)
Cooked Meat Medium is recommended for the cultivation of aerobic, microaerophilic, and anaerobic microorganisms, especially Clostridium species
The use of animal tissue for culturing anaerobic organisms was first employed by Theobald Smith in 1890. Von Hibler later used brain tissue for cultivating and classifying anaerobic bacilli. Robertson replaced brain tissue with beef heart and used this medium to differentiate putrefactive and saccharolytic species.
The formulation presently used is a modified version of Robertson’s formulation. This medium is also referred to as
Chopped Meat Medium. Nutritional requirements needed by most bacteria are provided by beef heart, peptone and dextrose. Dextrose, yeast extract, hemin and vitamin K are added to enhance the growth of anaerobic microorganisms. Amino acids and other nutrients are supplied by the muscle protein in the heart tissue granules. Reducing substances, which permit the growth
of strict anaerobes, are supplied by the muscle tissue and the iron filings. It is thought that the meat particles act as a reducing and detoxifying substance, thereby disabling harmful by products that may be produced by the replicating organism. Because reducing substances are more available in denatured protein, the meat particles are cooked before use in the medium.
Growth of spore-forming and non-spore-forming obligate anaerobes is supported by this medium. Cooked Meat Medium is also useful as an enrichment broth for cultivating organisms from a very small inoculum.
Additionally, researchers have found that Cooked Meat Medium preserves viability of organisms over a long period of time and is useful in maintaining anaerobic stock organisms. The Food and Drug Administration recommends its use in the enumeration and identification of Clostridium perfringens from food.
