Abstract: An uncertainty evaluation method for the microbiological determination of biotin in infant formula was developed in order to control the quality of test results and improve the detection accuracy, a method for uncertainty evaluation of milk powder by method was established. According to the requirements of the Evaluation and Expression of Uncertainty in Measurement (JJF 1059.1—2012) and the Guide to the Evaluation and Expression of Uncertainty in Measurement (GB/T 27418—2017), the uncertainty components were estimated for the determination of biotin in infant formula by the method specified in the National Food Safety Standard Determination of Biotin in Foods (GB 5009.259—2016). It was found that the greatest uncertainty resulted from standard curve fitting and repeatability test. The uncertainty for the biotin content of three infant formula samples was as follows: sample A (19.87 ± 2.84) μg/100 g, B (30.35 ± 4.41) μg/100 g, and C (53.15 ± 7.15) μg/100 g (in the 95% confidence interval, coverage factor (k) = 2). As the content of biotin in samples increased, the expanded uncertainty also increased.

Key words: microbiological method; infant formula; biotin; uncertainty; evaluation

摘要： 建立微生物法测定婴幼儿配方乳粉中生物素含量的不确定度评定方法，以进行检测结果的质量控制，提高检测数据的准确性。按照GB 5009.259—2016《食品安全国家标准 食品中生物素的测定》进行婴幼儿配方乳粉中生物素含量的检测，根据JJF 1059.1—2012《测量不确定度评定与表示》和GB/T 27418—2017《测量不确定度评定和表示》等要求，对检测过程中产生的各不确定度分量进行评定，合成标准不确定度。结果表明：标准曲线拟合和重复性检测产生的不确定度最大；婴幼儿配方乳粉中3 个含量生物素的不确定度报告：样品A（19.87±2.84） μg/100 g，样品B（30.35±4.41） μg/100 g，样品C（53.15±7.15） μg/100 g（置信区间95%，包含因子k=2）；随着样品中生物素含量的增高，检测结果的扩展不确定度也随之增大。

关键词: 微生物法；婴幼儿配方乳粉；生物素；不确定度；评定