This monograph has been assessed by members of the IUMS–ICFMH Working Party on Culture Media and given ‘Approved’ status.

This is a diagnostic selective medium formulated by Holbrook and Anderson (1980) for the enumeration of Bacillus cereus in foods. Selectivity is attained with polymyxin and a critical concentration of nutrients. Cycloheximide may be used to inhibit the growth of moulds. Bacillus cereus is identified by colony form, colour and egg yolk hydrolysis and rapidly confirmed by cell and spore morphology. Bacillus anthracis, Bacillus mycoides, Bacillus pseudomycoides, Bacillus thuringiensis and Bacillus weihenstephanensis may not be distinguishable from Bacillus cereus. Incubation at 30°C allows the growth of psychrotolerant strains of this group.