Factors affecting germination and growth of Bacillus cereus spores in milk.

The effect of salt concentration, acidity, and storage temperature on the spore germination of Bacillus cereus and the growth rate of the organism was investigated. Increasing the amount of salt to more than 5% or acidifying the milk to pH 5.0 or 4.5 greatly affected the germination and growth of B. cereus spores. When a culture of Streptococcus lactis was used as an acidifying agent, B. cereus showed a normal growth rate during the first 12 h, followed by a sharpe reduction in numbers. When B. cereus spores were inoculated in reconstituted dry milk or baby food, a higher multiplication rate was obtained at 30 degrees C than at 8 degrees C.