Melamine appears to have adulterated three high-protein ingredients from China that went into pet food.
In late April, the Food and Drug Administration was investigating the theory that the adulteration was purposeful, among other possibilities. Adding melamine to an ingredient could increase the protein reading during chemical analysis.
The FDA detected melamine originally in wheat gluten and more recently in rice protein concentrate from China that went into pet food for the U.S. market. Royal Canin detected melamine in corn gluten from China that went into pet food for the South African market, according to media reports.
Natural Balance Pet Foods was first to announce that melamine had adulterated rice protein concentrate, a new ingredient in several products. Natural Balance recalled the products following complaints that pets developed renal failure after eating the food.
Wilbur-Ellis, which imported the rice protein concentrate from China, recalled all lots of the ingredient. According to Wilbur-Ellis, the word "melamine" appeared on a single pink bag among white bags of rice protein concentrate in a recent shipment from Binzhou Futian Biology Technology.
Blue Buffalo, Royal Canin USA, SmartPak, and Drs. Foster & Smith subsequently recalled products containing rice protein concentrate from Wilbur-Ellis.
Hog farms bought some salvage pet food containing the rice protein concentrate. Tests found melamine in the urine of hogs in California, North Carolina, and South Carolina. Some salvage pet food went to other hog farms in New York, Utah, and possibly Ohio. At press time, most of the farms were under quarantine or other movement restrictions. A poultry farm in Missouri also might have received adulterated food.
The original detection of melamine in wheat gluten from Xuzhou Anying Biologic Technology Development led to massive recalls of pet food. The FDA is screening all wheat gluten, rice protein concentrate, and corn gluten coming from China. The agency is detaining shipments of wheat gluten from Xuzhou Anying and rice protein concentrate from Binzhou Futian.
The FDA is testing for melamine in samples of other high-protein ingredients—specifically cornmeal, soy protein, and rice bran—with a focus on imports from China. At press time, the agency had just received the invitation it sought from the Chinese government to send inspectors to the country.