1. Food Composition Laboratory (FCL), Beltsville Human Nutrition Research Center (BHNRC), United States Department of Agriculture, Agricultural Research Service (USDA-ARS), Building 161, Beltsville, MD.
2. Retired, FCL, USDA.
3. Corresponding author. Phone 301-504-8927. Fax: 301-504-8314. E-mail: wayne.wolf@ars.usda.gov