Melamine made it back into the news this week as scientists at Consumers Union, a nonprofit watchdog group, called the Food and Drug Administration (FDA) out on their decision to allow US-manufactured food products, including infant formula, contaminated with melamine and cyanuric acid to be sold in the US. Consumers Union is not alone in its outrage at the FDA's response to melamine-contaminated foods reaching US shelves. Congresswomen Rosa L. DeLauro, chairwoman of the Agriculture – FDA Appropriations Subcommittee, released a statement back in October chastising the FDA for their lax approach on this issue. That was before trace amounts of either melamine or cyanuric acid were found in all 3 major brands of US formula. The FDA discovered melamine or cyanuric acid in 4 of the 89 infant formula containers they tested in the fall of 2008. More alarming is that the FDA did not release this information until the Associated Press filed a Freedom of Information Act request.
Melamine is a nitrogen rich compound found in plastics, adhesives and pesticides. In China, melamine was intentionally added to raw milk to disguise the fact that the milk had been watered down. In the US, melamine most likely finds its way into food products by unintentional contamination secondary to its legal use in food packaging. Although melamine can be dangerous in large quantities when ingested alone, as was the case in China, it can cause health problems at lower levels when combined with cyanuric acid. According to the World Health Organization (WHO), cyanuric acid can be an impurity of melamine.
In China, the tainted infant formula contained 2500-6000 parts per million (ppm) of melamine, whereas US formulas contaminated with melamine have all had less than 0. 5ppm. Yet what, if any, is a safe level of melamine? Prior to October, the FDA had no official policy regarding melamine except that it is not approved to be directly added to food in the United States. Since October, the FDA has declared that food containing less than 1 ppm of melamine is safe. The WHO has stated that an individual's total daily limit of melamine should not to exceed 0.2mg/kg of body weight/day. The Canadian government has voiced the concern that even if the small amounts of melamine and cyanuric acid found in individual cans of infant formula are safe, some infants use multiple ready-to-feed bottles a day and could therefore ingest a larger amount of the toxin. To ensure that infants stay within the safe range, even when consuming multiple bottles a day, the Canadian government has lowered its allowable level of melamine in infant formula from 1ppm to 0.5ppm.
Infants are an especially vulnerable group. This is because infants are not born with fully developed kidneys. Their kidneys continue to mature over the first year of life. It is for this reason that infants should not consume large amounts of water or salt and why it is so important that powdered infant formula be mixed correctly. Thus, it stands to reason that the amount of melamine an adult kidney can clear safely, may still be too much for an infant's kidney to handle.
The FDA may be taking a lax approach to melamine in order to avoid panic. Hopefully their desire to calm fears is not putting US infants at an unnecessary risk. We should not accept a tolerable level of toxins in our food. As is usually the case, if a food can be made safer than that should be the goal.
UPDATE: 1/22/09 - China Sentences 3 People To Death For Involvement in Melamine Scandal