THE OCCURRENCE OF BACILLUS CEREUS IN MILK AND ON DAIRY EQUIPMENT

SUMMARY: In a survey of milk obtained from individual farms and creameries, 87% of samples were found to contain fewer than one cell of Bacillus cereus /ml. The remaining 13%, although they all yielded low counts, showed that the organism tended to occur in milk received from particular farms and creameries. On investigating sources of contaminated milk, it was found that the organism was derived chiefly from cans which, after being emptied of milk, had been allowed to stand for a long time before being washed properly and 'sterilized'. The vegetative cells of B. cereus were shown to form spores readily in thin films of diluted milk, such as may occur in a rinsed can.