Recent developments in food-matrix Reference Materials at NIST

Since 1996, the National Institute of Standards and Technology (NIST) has d eveloped several food-matrix Standard Reference Materials (SRMs) characteri zed for nutrient concentrations. These include SRM 1544 Fatty Acids and Cho lesterol in a Frozen Diet Composite, SRM 1546 Meat Homogenate, SRM 1548a Ty pical Diet, SRM 1566b Oyster Tissue, SRM 1846 Infant Formula, and SRM 2383 Baby Food Composite. Three additional materials - SRM 1946 Lake Superior Fi sh Tissue, SRM 2384 Baking Chocolate, and SRM 2385 Spinach - are in prepara tion. NIST also recently assigned values for proximate (fat, protein, etc.) , individual fatty acid, and total dietary fiber concentrations in a number of existing SRMs and reference materials (RMs) that previously had values assigned for their elemental composition. NIST has used several modes for a ssignment of analyte concentrations in the food-matrix RMs, including the u se of data provided by collaborating laboratories, alone and in combination with NIST data. The use of data provided by collaborating food industry an d contract laboratories for the analysis of food-matrix RMs has enabled NIS T to provide assigned values for many analytes that NIST does not have the resources or analytical expertise to measure.