Modified Differential Clostridial Brothfor enumeration of Clostridia from foodtuffs and other samples by MPN technique.This medium was developed for the enumeration of spores of sulphate reducing Clostridia in dried foods. by MPN technique. It is differential by means of detecting the ability of organisms to reduce sulphite to sulphide and thereby form iron sulphide, a black coloured complex.This medium is non-selective as other bacteria can also produce sulphide. Therefore, to enumerate Clostridia, pasteurization must be done to remove the vegetative cells.