包装饮用水中铜绿假单胞菌检验不确定度的评定

Uncertainty Evaluation of Pseudomonas Aeruginosa in Packaged Water for Drinking

为了探讨和建立包装饮用水中铜绿假单胞菌检验不确定度的评定方法。依据《测量不确定度评定与表示》(JJF1059-1999)和《食品安全国家标准饮用天然矿泉水检验方法》(GB 8538-2016),以及相关统计学方法分析其不确定度的主要来源,计算各个不确定度的分量,最后对各个分量进行合并计算最终测定结果的扩展不确定度。通过对实验结果的分析得到其主要不确定度来源于重复性测定和样品量取体积,其相对标准不确定度分量分别为0.0055和0.0193,合成不确定度为0.0201,扩展不确定度为0.0402,(k=2)。包装饮用水中铜绿假单胞菌的检测结果为(68~82)CFU/250mL。本文采用的评定方法,可以对单个包装饮用水样品铜绿假单胞菌检测结果不确定度作出估计,比较适用于日常检测中铜绿假单胞菌的不确定度评定。

This Paper aims to study and develop the uncertainty evaluation methods in detection of Pseudomonas Aeruginosa in packaged water for drinking. Based on GB/T 27411-2012 routine methods for evaluation and expression of measurement uncertainty in testing laboratory, GB 8538-2016 national food safety standards methods for examination of drinking natural mineral water,and related statistical methods to evaluate uncertainty of the samples,the sub-uncertainty was calculated an used to obtain combined uncertainty and expanded uncertainty of the measurement results. The results showed that the uncertainty was mainly derived from repeated experiments of samples and sample volume and had a nonnegligible effect on it with relative standard uncertainty values of 0.0055 and 0.0193,respectively.The combined standard uncertainty of the measurement results was 0.0201,and the expanded uncertainty was 0.0402.The final result of Pseudomonas Aeruginosa in packaged water for drinking was（68 ~82）CFU/250 mL. Evaluation method used in this study can estimate the uncertainty of test results of a single barreled water sample,which is suitable to evaluate uncertainty of Pseudomonas Aeruginosa in the daily work.