WANG D I, SCHARER J, HUMPHREY A E
Appl Microbiol. 1964 Sep;12(5):451-4. doi: 10.1128/am.12.5.451-454.1964.
The kinetics of death of Bacillus stearothermophilus spores (FS 7954) suspended in phosphate buffer (pH 7) were studied over a temperature range of 127.2 to 143.8 C and exposure times of 0.203 to 4.150 sec. These short exposure were achieved by use of a tubular flow reactor in which a suspension of spores was injected into a hot flowing stream at the entrance of the reactor. Thermal equilibria of the suspension with the hot stream was achieved within 0.0006 sec. After flow through a fixed length of reactor, the stream containing the spores was cooled by flash vaporization and then assayed for viable count. The death rate data were fitted by a logarithmic expression. However, logarithmic death rate was only approximated in the tail or high-kill regions of exposure. Death rate constants obtained from this portion of the data were found to correlate by Arrhenius as well as Absolute Reaction Rate Theory relationships. Thermal-death time curves were found to correlate the data rather poorly. The activation energy and frequency constant for an Arrhenius relationship fit of the data were found to be 83.6 kcal/gmole and 10(47.2) min(-1), respectively. The standard enthalpy and entropy changes for an Absolute Reaction Rate Theory relationship fit of the data were found to be 84.4 kcal/gmole and 157 cal/gmole-K, respectively.
研究了嗜热脂肪芽孢杆菌孢子（FS 7954）悬浮于磷酸盐缓冲液（pH 7）中，在127.2至143.8℃温度范围以及0.203至4.150秒暴露时间下的死亡动力学。这些短时间暴露是通过使用管式流动反应器实现的，在反应器入口处将孢子悬浮液注入热的流动 stream 中。悬浮液与热 stream 在0.0006秒内达到热平衡。在流经固定长度的反应器后，含有孢子的 stream 通过闪蒸冷却，然后测定活菌数。死亡速率数据用对数表达式拟合。然而，对数死亡速率仅在暴露的尾部或高杀灭区域近似。从该部分数据获得的死亡速率常数通过阿累尼乌斯以及绝对反应速率理论关系相关联。发现热死时间曲线与数据的相关性很差。对于数据的阿累尼乌斯关系拟合，活化能和频率常数分别为83.6千卡/克分子和10(47.2)分钟(-1)。对于数据的绝对反应速率理论关系拟合，标准焓变和熵变分别为84.4千卡/克分子和157卡/克分子-K。
