能力验证乳粉中大肠菌群计数不确定度评定

Uncertainty Evaluation of Coliform Count in Milk Powder by Proficiency Testing

目的:评定能力验证乳粉样品的大肠菌群计数不确定度。方法:依据JJF 1059.1-2012《测量不确定度评定与表示》评定所检测样品的大肠菌群计数结果的不确定度。结果:大肠菌群计数检测结果发散性较大,取其对数后再进行贝塞尔公式的计算,扩展不确定度为U=0.044 272(以对数计),包含因子k=2.26。

Objective:To evaluate the uncertainty of coliform count in proficiency testing sample of milk powder.Methods:According to JJF 1059.1-2012 Evaluation and expression of uncertainty in measurement,the uncertainty of the coliform count in detected samples was evaluated.Results:Thedata of coliform count were divergent,sothe logarithm of the data is taken before applying Bessel’s formula.Taking k=2.26,the expanded uncertainty was 0.044 272(in logarithmic).