Through its commodity program, the U.S. Department of Agriculture (USDA) provides commodity foods at no cost to schools taking part in the national school meals programs. Commodities include raw ground beef, cheese, poultry, and fresh produce. Like federal food safety agencies, the commodity program has taken steps designed to reduce microbial contamination that can result in severe illness. US Government Accountability Office (GAO) was asked to review (1) the extent to which the program's purchasing specifications related to microbial contamination differ from federal regulations, (2) the extent to which specifications for raw ground beef differ from those imposed by some other large purchasers, and (3) examples of schools' practices to help ensure that food is not contaminated. GAO compared the program's purchasing specifications to federal regulations for food sold commercially, gathered information from seven large purchasers of ground beef, and interviewed officials in 18 school districts in five states, selected in part because of their purchasing practices. GAO recommends, among other things, that USDA strengthen its oversight of food purchased by its commodity program, by establishing a more systematic and transparent process to determine whether additional specifications should be developed related to microbial contamination. USDA generally agreed with GAO's recommendations and provided technical comments. Appended are: (1) Objectives, Scope, and Methodology; and (2) GAO Contact and Staff Acknowledgments. (Contains 2 tables and 8 footnotes.)