He Mei, Xie Jianbin, Tang Huacheng, Men Jianhua
Institute of Nutrition and Food Satety, China CDC, Beijing 100050, China.
Wei Sheng Yan Jiu. 2007 Nov;36(6):703-5.
To observe the lab variety of sodium analysis of prepackaged from different labs of China.
Fourteen foods from seven kinds of foods were selected as food samples, including cereal products, bean products, meat products, dairy products, beverages, nuts, snacks, according to national prepackaged foods consumption survey results in 2000. The sodium concentrations were analyzed parallelly for three times by national standard methods in seven labs in China.
The 78.6% results were up to grade by Grubbs, Cochran and Dixon screening methods. The accuracy of protein analysis was expressed by variety co efficiency (C. V%). The C. V% of inner labs was from 2.46% to 7.82%. Besides walnut (with very low sodium content), the C. V% of inter labs and total labs were from 6.40% to 51.86% and from 6.88% to 52.16% (average 24.60%). The relative expanded uncertainty of protein detection was from 12.66% to 96.16% (average 46.02%).
Sodium analysis in labs in China were fit for national standards. If sodium labeling were focused on middle and high sodium contents prepackaged foods, the uncertainty of analysis could be controlled in 50%. The sodium detection level of labs in China should be promoted that the analysis variety of low content food could be reduced.
观察中国不同实验室对预包装食品钠分析的实验室差异。
根据2000年全国预包装食品消费调查结果，从谷物制品、豆制品、肉制品、乳制品、饮料、坚果、零食7类食品中选取14种食品作为食品样本。在中国7个实验室采用国家标准方法对钠浓度进行3次平行分析。
采用格拉布斯（Grubbs）、科克伦（Cochran）和狄克逊（Dixon）筛选方法，78.6%的结果符合等级要求。蛋白质分析的准确性用变异系数（C.V%）表示。各实验室内部的C.V%为2.46%至7.82%。除核桃（钠含量极低）外，各实验室之间和所有实验室的C.V%为6.40%至51.86%以及6.88%至52.16%（平均24.60%）。蛋白质检测的相对扩展不确定度为12.66%至96.16%（平均46.02%）。
中国实验室的钠分析符合国家标准。如果钠标签关注中高钠含量的预包装食品，分析不确定度可控制在50%以内。中国实验室的钠检测水平有待提高，以减少低含量食品的分析差异。
