Xu Sa, Labuza Theodore P, Diez-Gonzalez Francisco
Department of Food Science and Nutrition, University of Minnesota, 1334 Eckles Avenue, St. Paul, Minnesota 55108, USA.
J Food Prot. 2008 Feb;71(2):333-8. doi: 10.4315/0362-028x-71.2.333.
The combined effect of heat and hydrogen peroxide (HP) on the inactivation of avirulent Bacillus anthracis spores (Sterne strain 7702; strain ANR-1, an avirulent Ames derivative lacking the pXO2 plasmid; and strain 9131, a plasmid-less Sterne strain) was evaluated in milk. The study temperature ranged from 90 to 95 degrees C, and the concentration of added HP varied from 0.05 to 0.5%. Decimal reduction times (D-values) were determined using a sealed capillary tube technique. The mean D- and z-values of hydrated freeze-dried spores of all three strains in milk ranged from 550 s at 90 degrees C to 180 s at 94 degrees C and from 8.6 to 9.0 degrees C, respectively. When 0.05% HP was added to the milk, the D-values were decreased at least threefold, and at 0.5% HP the D-values ranged from 1 to 10 s. At 90 degrees C, all three strains had similar D-values when 0.05% HP was added. Increasing the concentration of HP to 0.5% had a greater reducing effect on the D-value for strain 7702 than on the values for strains ANR-1 and 9131. The rate of inactivation of each strain followed first-order reaction kinetics at each temperature-peroxide combination. Equations in the form of D = Constant x (HP concentration)n had R2 values greater than 0.97 for strains ANR-1 and 7702 and of at least 0.7 for strain 9131. This study suggests that a combination of high temperature (from 90 to 95 degrees C) and HP could be used for inactivation of B. anthracis spores in the event of deliberate contamination of milk such that the contaminated milk could be disposed of safely.
在牛奶中评估了加热和过氧化氢（HP）对无毒炭疽芽孢杆菌孢子（Sterne菌株7702；ANR - 1菌株，一种缺乏pXO2质粒的无毒Ames衍生物；以及9131菌株，一种无质粒的Sterne菌株）灭活的联合作用。研究温度范围为90至95摄氏度，添加的HP浓度从0.05%至0.5%不等。使用密封毛细管技术确定十进制减少时间（D值）。所有三种菌株的水合冻干孢子在牛奶中的平均D值和z值分别在90摄氏度时为550秒至94摄氏度时为180秒，以及8.6至9.0摄氏度。当向牛奶中添加0.05%的HP时，D值至少降低了三倍，而在添加0.5%的HP时，D值范围为1至10秒。在90摄氏度时，添加0.05%的HP时，所有三种菌株的D值相似。将HP浓度增加到0.5%时，对7702菌株的D值的降低作用比对ANR - 1菌株和9131菌株的D值的降低作用更大。在每个温度 - 过氧化物组合下，每种菌株的失活速率均遵循一级反应动力学。对于ANR - 1菌株和7702菌株，形式为D =常数×（HP浓度）^n的方程的R²值大于0.97，对于9131菌株至少为0.7。本研究表明，在牛奶被故意污染的情况下，高温（90至95摄氏度）和HP的组合可用于灭活炭疽芽孢杆菌孢子，从而使受污染的牛奶能够安全处置。
