Microbiology of food and animal feeding stuffs — Horizontal method for the enumeration of presumptive Bacillus cereus — Colony-count technique at 30 degrees C

ISO 7932:2004 specifies a horizontal method for the enumeration of viable Bacillus cereus by means of the colony-count technique at 30 °C. It is applicable to products intended for human consumption and the feeding of animals, and environmental samples in the area of food production and food handling.

In order to have a practicable test method, the confirmatory stage has been restricted to the typical aspect on MYP agar and the haemolysis test. Thus the term presumptive has been introduced in order to acknowledge the fact that the confirmatory stage does not enable the distinction of B. cereus from other closely related but less commonly encountered Bacillus species, such as B. anthracis, B. thuringiensis, B. weihenstephanensis, B. mycoides. An additional motility test may help to differentiate B. cereus from B. anthracis in cases where the presence of the latter is suspected.