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United States Department of Agriculture

Agricultural Research Service

Title: Quality and Performance Evaluation of Reference Materials for the Determination of Nutrients in Foods

Authors
item Phillips, Katherine - VA POLYTECHNIC INTITUTE
item Wolf, Wayne
item Patterson, Kristine
item Sharpless, Katherine - NIST, GAITHERSBURG, MD
item Amanna, Karen - VA POLYTECHNIC INTITUTE,
item Holden, Joanne

Submitted to: Accreditation and Quality Assurance: Journal for Quality, Comparability and Reliability in Chemical Measurement
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: December 29, 2006
Publication Date: April 1, 2007
Citation: Phillips, K.M., Wolf, W.R., Patterson, K.K., Sharpless, K.E., Amanna, K.R., Holden, J.M. 2007. Quality and performance evaluation of reference materials for the determination of nutrients in foods. Accreditation and Quality Assurance: Journal for Quality, Comparability and Reliability in Chemical Measurement. 12(3-4):126-133.

Interpretive Summary: Certified reference materials (CRMs) have been widely used in the USDA's National Food and Nutrient Analysis Program (NFNAP). Six hundred and ninety (690) assigned values for individual nutrients were compiled from the certificates of analysis for 63 food matrix CRMs. Across all nutrients, 36.5% of the uncertainty intervals (UI) for these CRMs were greater than 10% of the assigned values. These high UIs in the best available standards reflect the limits of precision and accuracy that can be obtained by current measurement systems for these components and have implications for producers of food matrix CRMs to provide higher precision materials. As part of the NFNAP, CRMs were submitted to contract labs, blinded, in the routine sample stream. Over 6.5 years (1999-2006), a total of 2629 values reported by nine laboratories for 259 certified nutrient concentrations in 26 CRMs were obtained. For some nutrients [dietary fiber, thiamin, folate, pantothenic acid, tocopherols, and carotenoids] greater than 25% of all laboratory values for these CRMs fell significantly outside of acceptable intervals. These data reflect the quality of data that can be generated for inclusion in the USDA Nutrient Database for Standard Reference. These data will be used by Government and private food analysis labs.

Technical Abstract: Certified reference materials (CRMs) play a critical role in validating the accuracy of analytical data and have been used extensively in the USDA's ongoing National Food and Nutrient Analysis Program (NFNAP), which generates contract analytical food composition data for inclusion in the USDA National Nutrient Database for Standard Reference. A total of 690 assigned values for individual nutrients were compiled from the certificates of analysis for 63 food matrix CRMs. Across all nutrients, 36.5% of the uncertainty intervals (UI) for these CRMs were greater than 10% of the assigned values. These high UIs in the best available standard materials reflect the limits of precision and accuracy that can be obtained by current measurement systems for these components. As part of the NFNAP, CRMs were submitted to contract laboratories, blinded, in the routine sample stream. Over a 6.5 year period (1999-2006) a total of 2629 values reported by nine laboratories for 259 certified nutrient concentrations in 26 CRMs were obtained. For some nutrients (dietary fiber, thiamin, folate, pantothenic acid, tocopherols, and carotenoids) greater than 25% of all laboratory values for these CRMs fell significantly outside of acceptable intervals.

Last Modified: 11/28/2014
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