金 丹，谢柳佳，李盼盼，张珍珍*，李博洋，栗晓瑞，毕 煜，吕逸凡，宋佳昕

（恒枫食品科技有限公司，浙江 杭州 310000）

摘 要：本文应用冻干乳粉质控样测定菌落总数的范围，并对实验过程中所引入的不确定度进行分析评价，评价最 终结果的不确定度范围。结果表明在置信水平95%，自由度15的条件下，扩展不确定度为0.0821，质控样品的菌 落总数取值范围为900CFU/mL～1300CFU/mL，包含因子 k=2.131，因样品特性区间为 790CFU/mL～2200CFU/ mL，实验检测值在相关特性区间内。对质控样品菌落总数测定的不确定度进行分析，影响其检测结果的不确定度 主要为重复性测量环节、稀释液制备环节、样品梯度稀释环节、移取样液体积环节这四步引入。 关键词：质控样；菌落总数；不确定度

Evaluation of Measurement Uncertainty for Total Number of Colonies in Quality Control Samples

JIN Dan，XIE Liu-jia，LI Pan-pan，ZHANG Zhen-zhen*，LI Bo-yang，LI Xiao-rui，BI Yu，LYU Yi-fan，SONG Jia-xin

（Ever Maple Food Science & Technology Co.，Ltd.，Hangzhou 310000，China）

Abstract: In this paper，freeze-dried milk powder quality control samples were used to determine the total number of colonies，and the uncertainty introduced in the experiment process was analyzed to evaluate the uncertainty range of the final result. The results showed that under the condition of 95% confidence level and 15 degrees of freedom，the expanded uncertainty was 0.0821，and the total number of colonies in quality control samples ranged from 900 to 1300CFU/mL，including factor k=2.131. Because the sample characteristic range was 790～2200CFU/mL，the experimental detection value was within the relevant characteristic range. The uncertainty of the determination for the total number of colonies in quality control samples was analyzed. The uncertainty affecting the detection results was mainly introduced in four steps：repetitive measurement，diluent preparation，sample gradient dilution and sample volume shifting.

Key words: quality control sample; total number of colonies; uncertainty

中图分类号：R446.5    文献标志码：A     文章编号：1007-7871（2025）04-0017-04

2025，Vol.28，No.4