However , cyanuric are not of concern in levels below 100 parts per billion . Official says FDA has tested 74 samples of U.S.-made baby formula . Some samples tested positive but at safe levels , official says . These are far below those tested with Chinese formula .
Melamine , cyanuric acid not of concern in levels below 1,000 parts per billion . Official says FDA has tested 74 samples of U.S.-made baby formula . Some samples tested positive but at safe levels , official says . Levels are far below those associated with Chinese contamination .