Well-characterized food-matrix reference materials are critical to facilitate compliance with nutritional labeling laws, provide traceability for food exports, improve the accuracy of label information for packaged foods, and contribute to studies of human nutritional status. Enactment of the Infant Formula Act of 1980 and the Nutrition Labeling and Education Act (NLEA) of 1990 resulted in requirements for labeling of processed and packaged foods in the US. Some nutrients (e.g., calories, fat, cholesterol) must be declared on the label, while information about other nutrients can be included at the manufacturer’s discretion. However, all nutrient declarations must be accurate and within thresholds set by the regulatory agency (i.e., U.S. Food and Drug Administration (FDA) or the U.S. Department of Agriculture (USDA)). In support of compliance with these regulations, the CSD has developed a series of food-matrix reference materials characterized for mass fractions of common nutrients. The selection of commodities for reference material development was strongly informed by the AOAC INTERNATIONAL triangle model for classification of foods into groups with similar composition . The AOAC food triangle is based on the relative levels of fat, protein, and carbohydrate in the food, and built on the premise that foods with similar macronutrient profiles will offer similar analytical challenges for determination of micronutrients. Food-matrix reference materials are developed from animal, plant, and mixed-matrix sources to represent common food types with various macronutrient profiles [2, 3]. These reference materials are used by laboratories involved with the characterization of food composition (e.g., food manufacturers and processors, regulators, third-party testing laboratories) to develop and validate new analytical methods, to improve the quality of their analytical measurements, and to support compliance with a number of federal regulations enforced by the FDA and USDA .