Zhou X, King V M
Buckman Laboratories International, Inc, Memphis, TN 38108, USA.
J Ind Microbiol. 1995 Aug;15(2):103-7. doi: 10.1007/BF01569807.
An efficient impedance method was developed for rapid evaluation of cosmetic preservatives. The method used decimal reduction time or D-value to assess preservative efficacies. The D-value, which was calculated from the plot of Log CFU ml-1 versus time by linear regression analysis, could be obtained within 48 h. Thus, the time required for the challenge test was reduced from 4-8 weeks with the standard procedures (eg US Pharmacopeia), to 2 days with the current method. A calibration curve (r = -0.95) was established by plotting the Log CFU ml-1 versus capacitance detection time (DT) of 108 samples. With the calibration, CFU can be estimated directly from the impedance test without plating. Two commercial biocides and several other chemicals were evaluated in a shampoo by the impedance procedure against Pseudomonas aeruginosa. The D-values obtained from the impedance test were not significantly different from those produced by the conventional plate count method. The technique was found to be particularly useful when screening a large number of compounds to find novel preservatives and synergistic preservative combinations.
开发了一种高效的阻抗方法用于快速评估化妆品防腐剂。该方法使用十进制减少时间或D值来评估防腐剂的功效。通过线性回归分析从Log CFU ml-1对时间的图中计算得到的D值可在48小时内获得。因此，挑战试验所需的时间从标准程序（如美国药典）的4 - 8周减少到了当前方法的2天。通过绘制108个样品的Log CFU ml-1对电容检测时间（DT）建立了校准曲线（r = -0.95）。通过该校准，无需平板培养即可直接从阻抗测试中估计CFU。通过阻抗程序在洗发水中针对铜绿假单胞菌对两种商业杀菌剂和其他几种化学品进行了评估。从阻抗测试获得的D值与传统平板计数法产生的D值没有显著差异。当筛选大量化合物以寻找新型防腐剂和协同防腐剂组合时，发现该技术特别有用。
