化妆品菌落总数指标测量不确定度的评定

Uncertainty assessment in the detection of aerobic bacterial count in cosmetics

目的评定化妆品中菌落总数指标检测的测量不确定度。方法依据《化妆品卫生规范》(2007年版)检测化妆品的菌落总数指标,分析菌落总数测量不确定度的来源,采用指数法评定化妆品中菌落总数的测量不确定度。结果化妆品菌落总数检验过程中不确定度来源主要是样品重复测量带来的不确定度,在包含率为95%时,本实验化妆品中菌落总数检测结果的扩展不确定度Up为0.038。lgx=lgx±Up,以第一组检测结果为例lgx=3.764,则lgx取值区间为3.726~3.802,取反对数后,2次测量的平均值的取值区间为5 321 cfu/ml^6 339 cfu/ml。结论可用指数法对化妆品中菌落总数测量不确定度进行评定,评定测量结果的不确定度对提供准确可靠的数据具有重要意义。

Objective To assess the uncertainty of aerobic bacterial count in cosmetics. Methods The aerobic bacterial count was detected based on Hygienic Standard for Cosmetics. The source of the uncertainty in the detection was analyzed, and index method was adopted to assess the uncertainty of aerobic bacterial count detection. Results The main source of the uncertainty of aerobic bacterial count in cosmetics was repeated measurement of samples. As the coverage probability was 95%, the expand- ed uncertainty（ Up ） of aerobic bacterial count in cosmetics was 0. 038. lgx = lgx ＋ Up, taking the first set of test results for ex- ample lgx = 3. 764, so lgx took range of 3. 726 - 3. 802, and after the opposition, the average of two measurements was among 5 321 cfu/ml-6 339 efu/ml. Conclusion The index method can be used to assess the uncertainty of aerobic bacterial count in cosmetics, and evaluating the uncertainty of measurement results has great significance to provide accurate and reliable data.