A blue-ribbon committee formed by the U.S. and European Union to study genetically engineered foods has recommended mandatory labeling and more careful testing of such foods. The committee, whose 20 members included opponents and fans of biotechnology, said late last month that stronger regulations would increase public confidence in the foods, a position that the U.S. Food and Drug Administration has denied in the past. In calling for mandatory labeling, however, the committee did not specify how much of a biotech component a food would have to include to require a label.