Analysis of total diet study foods for gamma-ray emitting radionuclides

Foods collected for radionuclide analysis under the Food and Drug Administration's (FDA's) Total Diet Study (TDS) Program were analyzed by the Center for Food Safety and Applied Nutrition (CFSAN) as quality assurance (QA) for analyses performed at FDA's Winchester Engineering and Analytical Center (WEAC). 200-ml QA portions were analyzed for gamma-ray emitting fission products and naturally occurring radionuclides. Efficiency, pileup correction, absorption effects, and accuracy were determined by analyzing a variety of certified reference materials and KNO3 and KCl solutions. 40K results agreed well with those from WEAC and with total K results from other techniques. Count times as low as 2 minutes were sufficient to confirm that radioactivity concentrations were below regulatory limits. (author)