Raevuori M, Genigeorgis C
Appl Microbiol. 1975 Jan;29(1):68-73. doi: 10.1128/am.29.1.68-73.1975.
The effects of NaCl concentration, pH, and water activity (aw) on the ability of vegetative cells of Bacillus cereus to initiate aerobic growth in brain heart infusion broth at 30 C were studied in a factorial design experiment. By using multiple regression techniques, equations were derived which related the decimal reduction of the bacterial population to the concentration of NaCl and pH of broth to which the population was exposed. From these equations, the percentage of inoculated cells capable of initiating growth could be calculated. The reliability of these equations in foods was tested in laboratory-processed meat and rice media. The foods were less inhibitory than the broths, so that accurate prediction of growth initiation in foods was not possible by using the developed formulas. The impact of this type of quantitative study on the development of specific microbial standards for foods is discussed. When the NaCl concentration is increased, the aw is decreased and, with increased deviation of pH from optimum, more concentrated inoculum of B. cereus cells is needed to assure initiation of growth in culture media and foods.
在一项析因设计实验中，研究了氯化钠浓度、pH值和水分活度（aw）对蜡样芽孢杆菌营养细胞在30℃脑心浸液肉汤中开始需氧生长能力的影响。通过使用多元回归技术，得出了将细菌群体的十进制减少量与群体所接触的肉汤中氯化钠浓度和pH值相关联的方程。根据这些方程，可以计算出能够开始生长的接种细胞百分比。在实验室加工的肉类和大米培养基中测试了这些方程在食品中的可靠性。食品的抑制作用比肉汤小，因此使用所开发的公式无法准确预测食品中的生长起始情况。讨论了这类定量研究对制定食品特定微生物标准的影响。当氯化钠浓度增加时，水分活度降低，并且随着pH值偏离最佳值的增加，需要更浓缩的蜡样芽孢杆菌细胞接种物来确保在培养基和食品中开始生长。
