酸奶中乳酸菌计数不确定度的评定  

Uncertainty evaluation of lactic acid bacteria count in yoghurt

作　　者：秦文 王丽媛 王晶波 卓勤 QIN Wen;WANG Li-yuan;WANG Jing-bo;ZHUO Qin(National Institute for Nutrition and Health,Chinese Center for Disease Control and Prevention,Beijing 100050,China)

机构地区：[1]中国疾病预防控制中心营养与健康所,北京100050

出　　处：《中国卫生检验杂志》2018年第15期1844-1846,共3页Chinese Journal of Health Laboratory Technology

摘　　要：目的评定酸奶中乳酸菌总数指标检测的测量不确定度。方法依据GB 4789.35—2016进行乳酸菌总数测定,依据JJF 1059.1—2012来评定酸奶中乳酸菌总数的测量不确定度。结果本次不确定度评定主要从贡献较大的样品称量、稀释、加样和重复检测等方面进行,在包含率为95%时,本实验酸奶样品中乳酸菌总数检测结果的扩展不确定度U为0.296 5。lgx=lgx±U,以第一组检测结果为例,lgx=9.358±0.296 5,则这份样品乳酸菌总数的lgx值区间为9.061 5~9.654 5,取反对数后,第一组样品乳酸菌总数的置信区间为(1.2~4.5)×109cfu/g。结论此方法适用于类似检测条件下乳酸菌计数不确定度的评定。Objective To assess the measurement uncertainty of lactic acid bacteria count in yoghurt. Methods The total number of lactic acid bacteria was determined according to GB 4789. 35—2016,and the uncertainty of total lactic acid bacteria in yogurt was evaluated according to JJF 1059. 1—2012. Results This uncertainty assessment is mainly conducted on the sample weighing,dilution,sample loading and repeated testing. As the coverage probability was 95%,the expanded uncertainty（U） of lactic acid bacteria count in yoghurt was 0. 296 5. lgx = lgx ± U,taking the first set of test results as an example,lgx = 9. 358 ± 0. 296 5,so lgx took range of 9. 061 5-9. 654 5,and after taking antilog,the confidence interval of the total number of lactic acid bacteria in the first group was（1. 2-4. 5） × 109 cfu/g. Conclusion The established method can be used in the uncertainty evaluation of lactic acid bacteria count under similar circumstances.

关 键 词：不确定度 酸奶 乳酸菌总数 

分 类 号：TS252.7[轻工技术与工程—农产品加工及贮藏工程]