"A second company likely imported rice protein from China that was contaminated with a chemical linked to a major pet food recall, two U.S. senators said on Monday. Rice protein tainted with the chemical melamine was used in pet foods from at least five manufacturers who obtained the protein from one supplier, U.S. officials have said. It also made its way into feed used at a California hog farm. Now, another company is suspected of importing rice protein from China, Democratic Sens. Richard Durbin of Illinois and Maria Cantwell of Washington said in a letter to the U.S. Food and Drug Administration."