Werdmuller G A, Boelsma S
State Institute for Quality Control of Agricultural Products (RIKILT), Wageningen, The Netherlands.
J Assoc Off Anal Chem. 1988 May-Jun;71(3):575-8.
For almost 25 years, the central government laboratory of The Netherlands has administered a continuous program for the quality control of dairy products. The analytical work is conducted by private laboratories but monitored by the government laboratory. The design and results obtained by this program are illustrated by the determination of water and milk solids-not-fat contents in butter, using data collected monthly over a period of 19 years. Under this strict system of control, the within-laboratory reproducibility (i.e., over an extended period) is almost equal to the between-laboratory reproducibility. Most of this within-laboratory variation is from month to month, indicating that in this case the time variability dominates the between-laboratory variability.
近25年来，荷兰中央政府实验室一直在实施一项持续的乳制品质量控制计划。分析工作由私人实验室进行，但由政府实验室监督。通过使用19年期间每月收集的数据，测定黄油中的水分和非脂乳固体含量，来说明该计划的设计和获得的结果。在这种严格的控制体系下，实验室内部的再现性（即在较长时期内）几乎等同于实验室间的再现性。这种实验室内部的变化大多是逐月变化，这表明在这种情况下，时间变异性主导了实验室间的变异性。
