Pinnacle™ Bacillus cereus MYP (ISO)

Product Code: PIN015

Introduced by Mossel and his co-workers in 1967 for the enumeration of Bacillus cereus in foods even with very low numbers, this formula was shown to be the most effective for this purpose by Inal in 1972.

Two reactions on this medium differentiate B. cereus from other members of the Bacillus group, these are mannitol fermentation and lecithinase production. Mannitol fermentation on this medium produces a yellow colour, B. cereus is mannitol negative and produces pink colonies. The lecithinase production of B. cereus is indicated by a heavy precipitate around the colonies.

If the plates contain numerous mannitol-fermenting microorganisms leading to the production of acid, then the characteristic pink colour of B. cereus colonies may be reduced or disappear entirely. Some strains of B. cereus produce only little or no lecithinase. Colonies of these strains will not be surrounded by a precipitation zone. These colonies should also be subjected to confirmation tests.

Polymyxin is added to suppress coliforms but some Proteus spp. and Gram positive cocci may grow through. This formulation conforms to ISO 7932-2004 and ISO 11133:2014.

Related Organism(s)

• Bacillus