Fifteen years after she lost her first baby to a rare and devastating birth defect, Andrea Lopez takes comfort in knowing that other Latina mothers might finally avoid the same pain. In January, California became the first state to require food makers to add folic acid, a crucial vitamin, to corn masa flour used to make tortillas and other traditional foods widely used in her community. It’s a long-delayed move aimed at reducing Hispanic infants’ disproportionately high rates of serious