Product Code: LAB220
Differential Reinforced Clostridial Medium ISO (DRCM) is a medium for the detection and enumeration of the spores of sulphite-reducing anaerobes as described in BS EN 26461-1.
Sulphite reducing anaerobes, in particular clostridia, can be indicators of remote and intermittent pollution. Widespread in the environment, being found in human and animal faeces, soil and waste water, the spores are more resistant to physical and chemical factors than vegetative cells and able to survive for long periods in water. The spores may also be resistant to chlorination at the levels commonly used in water treatment.
DRCM has been developed for use with the Most Probable Number (MPN) method to determine the MPN of anaerobes (Clostridia) per volume of sample. The formulation includes peptone, yeast extract, meat extract, starch & L-cysteine for nutrition with glucose providing the energy source. Sodium acetate provides partial selectivity.
Clostridia are able to reduce sulphite to sulphide — forming iron sulphide. Iron (III) citrate is included in the formulation as an indicator of sulphite reduction. Blackening in the medium indicates that iron sulphide has been formed and therefore that sulphite reduction has occurred.
Other bacteria are able to form sulphide, so vegetative cells must be first be removed from the test sample by an appropriate process e.g. heat treatment.