Melamine: What is it? Where does it come from? How did it get into our pet food and eventually make its way into animal feed and fish feed? What, if any, is the impact on human health and what efforts are in place to continue to protect the safety and integrity of the food we eat? These questions are part of an ongoing investigation that delves into the regulation of food imports and the infrastructure of food safety regulatory systems across the world.
The events that started in March 2007 as the largest pet food recall in U.S. history grew into a complex food safety issue. It was discovered that the same ingredients used in pet food contaminated with melamine had been used to produce farm animal feed and fish feed. In April alone, 107 food imports from China were held by the U.S. government, and, in May, warnings about tainted toothpaste from China were also disclosed. As a growing number of internationally-sourced foods become available on the U.S. market, it is important for Americans to be aware of the measures being taken to keep contaminated foods out of the marketplace.
Initially, numerous cat and dog illnesses were linked to the contaminated pet food, which triggered immediate voluntary recalls of more than 100 brand name products. Within 24 hours of being notified of the problem, FDA investigators visited the Kansas processing facility where the contaminated pet food was being produced and obtained samples of wheat gluten - a food ingredient desired for its higher protein content than wheat flour - used during production. The laboratory test results of these samples detected the presence of melamine. The source of the wheat gluten was traced back to a supplier in China, where it was quickly revealed that this was an intentional adulteration. The melamine was being added to wheat flour in order to pass it off as a higher quality wheat gluten product.
As the investigation continued, more announcements about tainted food imports were made by the FDA. In April, we learned this same contaminated wheat gluten was also being used in the production of livestock feed, which intensified investigations as the U.S. Department of Agriculture (USDA) became actively involved. While FDA regulates livestock feed, the USDA’s Food Safety and Inspection Service (FSIS) regulates meat and poultry used for human consumption. As concern grew and groups began making calls for a total ban on food imports from China, the FDA proactively subjected all vegetable proteins imported from China to detention. Both hogs and poultry fed rations supplemented with pet food scraps containing melamine and related compounds were initially held on their farms while the risk to human health was being studied.
A collaboration of scientists from the FDA, USDA, Centers for Disease Control and Prevention (CDC), Environmental Protection Agency and the Department of Homeland Security released an interim report called the “Interim Melamine and Analogues Safety/Risk Assessment.” Although the report is waiting for external scientific experts to review it before it can be finalized, the agency scientists concluded, “the consumption of pork, chicken, domestic fish and eggs from animals inadvertently fed animal feed contaminated with melamine and its analogues is very unlikely to pose a human health risk.” According to earlier testing, “a person weighing 132 pounds would have to eat more than 800 pounds per day of chicken [or pork] containing melamine and its compounds to approach a level of consumption that would cause a health concern.” As an added precaution, CDC used its surveillance network to monitor for signs of human illness, and no problems have been detected to date.
Melamine is a chemical traditionally used in the production of plastics, specifically fire-resistant and heat-tolerant industrial products, such as countertops, fabrics, cooking utensils, glues and flame retardants. It is not approved for use as a food ingredient in the U.S., which includes both domestic and foreign manufacturers whose products enter the U.S. food supply chain. Since the disclosure of the Chinese contaminations, it was also discovered that two U.S.-based feed manufacturers had been using melamine at much lower levels in fish and livestock feed in order to create a specific pellet form. By itself, melamine is not known to be highly toxic, so scientific investigators now think it is a mixture of melamine and another chemical—cyanuric acid—added to the Chinese wheat flour that is causing crystal formation in the kidneys of cats, dogs and other domesticated animals.
For more information on the evolution of the pet food recall, visit http://www.fda.gov/oc/opacom/hottopics/petfood.html, or check the FDA home page at www.fda.gov for frequently updated information. The FSIS notice regarding animal feed is at http://www.fsis.usda.gov/OPPDE/rdad/FRPubs/2007-0018.htm, and the interim safety and risk assessment on melamine and its analogues can be found at http://www.cfsan.fda.gov/~dms/melamra.html.
