牛乳菌落总数测定的不确定度评定

对牛乳样品菌落总数的测定结果进行不确定度评定，为检测过程的质量控制提供科学依据。依据GB 4789.2—2016《食品安全国家标准 食品微生物学检验 菌落总数测定》检测牛乳样品的菌落总数，按照JJF 1059.1—2012《测量不确定度评定与表示》分析该检测结果不确定度的来源并建立数学模型，然后分别对引入的不确定度分量进行评定，最终合成菌落总数测定的不确定度。结果表明：牛乳样品菌落总数测定结果的扩展不确定度为0.043 4，结果对数值取值区间为3.924，4.010]，该样品的菌落总数为8 395～10

Uncertainty Evaluation for the Determination of Aerobic Plate Count in Milk

In order to provide a scientific rationale for the quality control in the determination of aerobic plate count(APC)in milk,the measurement uncertainty was estimated.According to the national standard of China(GB 4789.2—2016),APC in samples was detected.The sources of uncertainty were analyzed according to Evaluation and Expression of Uncertainty in Measurement(JJF 1059.1—2012)and a mathematical model for uncertainty evaluation was established.The introduced uncertainty components were evaluated and finally the total combined uncertainty was established by combination of individual components.The results showed that the extended uncertainty for APC quantification in milk samples was 0.0434.The logarithm of APC was3.924,4.010],and from this,APC was calculated to be 8395–10233 CFU/mL.In conclusion,this procedure can effectively assess the measurement uncertainty in the determination of APC in milk.