Saturday, December 6, 2008

Melamine: How Much Is Too Much?

December 6, 2008

The World Health Organization convened a meeting of toxicology experts in Ottawa (Canada) this past week to figure out a Tolerable Daily Intake (TDI) of melamine. The expert panel arrived at a consensus of 0.2 milligrams of melamine daily per kilogram of body weight (one kilogram equals 2.2 pounds). 

This is a significant reduction from the previous working numbers of 0.5 mg/Kg (in Europe), and 0.63 mg/Kg on which the US Food and Drug Administration based its Interim Risk Assessment. The WHO announcement did not provide any details explaining the basis for the change.

An obvious question is whether this reduced TDI will alter the interim limit guidelines that have been applied around the world for melamine in food. At present, those guidelines stipulate a maximum of 2.5 ppm (i.e., 2.5 mg/Kg) of melamine in most foods and feeds. Foods intended to be the main source of nutrition for infants and toddlers (age cut-off of 36 months) must meet a stricter melamine limit of 1.0 ppm. 

It's easiest to answer the question by working through an example – a 3-year old child weighing 15 Kg (33 pounds). 

According to the new recommendations, this child can safely consume 3 milligrams of melamine daily (0.2 mg/Kg body weight, multiplied by 15 Kg). Assuming that all food contains the permitted limit of 2.5 ppm of melamine, the child would need to eat or drink 1.2 Kg – more than 2.6 pounds – of food and beverage every day in order to consume 3 milligrams of melamine. 

Using the same arithmetic, an adult weighing 70 Kg (154 pounds) would have to consume 5.6 Kg (more than 12 pounds) of food and beverage daily to reach his or her TDI of 14 milligrams of melamine. 

There are other considerations, of course. Not everyone will respond to melamine the same way. Individuals whose kidney functions already are impaired may be more susceptible to low doses of melamine. Infants and young children may be far more susceptible than adults. And no one knows to what extent the presence of other related compounds (such as cyanuric acid) may alter the health equation. For the moment, though, the current guidelines are likely to remain in force.

The WHO report states clearly that the TDI of 0.2 ppm is a Tolerable – not a safe – level for melamine. In principle, melamine should not be present in food. In practice, food can become contaminated by trace amounts of melamine from products used in food plant sanitation, from the metabolism of certain pesticides by crops, and by migration from food contact surfaces, such as melamine-based dish ware.

Until society finds a way to eliminate all possible sources of melamine contamination of our food supply, it would appear that we shall have to tolerate the possibility that we are ingesting melamine along with our meals.


  1. Thanks for the update Phyllis! I would only comment also that while tolerance levels are being set by WHO and FDA, who is policing food to ensure one is only receiving these "tolerable" amounts? FDA inspects less than 1% of US imports so what is the point of setting a level if it cant be checked and enforced? None of us truly know how much of these toxins we are ingesting each day. And did they take the accumulative effect into account as I had understood that these dont just flush out of ones system....

    While these toxins may be introduced thru what might be considered reasonable and valid sources such as plastic dishes, I dont think one should have to tolerate melamine and cyanuric acid that was purposely and illegally added to food. Im still shooting for NO melamine/cyanuric acid in human or pet food some day.

  2. Your points are well taken. Canada adopted what sounds like a sensible approach to ingredients from China meant for animal feed ( Every shipment is held at the border until the importer can provide the Canadian government with a certificate analysis FROM AN ACCREDITED LAB showing that the shipment does not exceed melamine tolerance levels. This puts the onus where it belongs, and allows the government to assume its proper role of enforcing, rather than spending tax money on random testing.

    The WHO report pointed out very clearly that the additive of more than one chemical (eg., melamine + cyanuric acid) in the diet is not known. The 2007 dog food fiasco would seem to indicate that the combined effect of those two chemicals is far more severe than the individual contaminants acting alone.

    I fully agree that the deliberate adulteration of food, whether for economic benefit or for something even more nefarious, is beyond the pale and must NOT be tolerated. But the only way to eliminate melamine and cyanuric acid traces from food and feed is to find alternatives to the cleaning agents, adhesives and pesticides that result in residues migrating into food.

  3. I have been a follower of the melamine fiasco since the 07' recall. Since people-food is now affected (we all predicted that back then), and we know that through the beef industry the stuff will make it into every beef byproduct, I am wondering if choosing organic milk for example would make any difference. The question really is do organic milk cows get the same feed as regular milk cows? Considering the guidelines of what is an organic food, do those guidelines alter the path of normal flow of feed for American beef? As Anonymous pointed out....we don't check the stuff so by default would the Organic industry be a help in this area?

  4. Doggles, if an organic milk cow truly is "organic", then she should be either grass-fed or feeding on grain that was raised without chemical fertilizer or pesticides. That doesn't GUARANTEE the absence of melamine traces, but it lowers the probability significantly.

    From what I've read, though, there is an FDA-approved adhesive used on food packaging which can leach traces of melamine into food. Is it used to form milk cartons? I don't know. I've also read that melamine traces can remain on food production equipment after the use of certain cleaners. Are these used in cleaning milk processing equipment? Again, I don't know. I'm still looking further into some of these issues, and will probably post a follow-up.

    I also don't know whether melamine will be excreted into milk by a cow that is fed melamine-contaminated feed.

  5. Yes Phyllis, you are can be leached in. I guess the only way to avoid that is to drink raw milk, which is usually stored in glass bottles. However, that doesn't cover the production equipment.
    Also, remembering the warnings of what can cross into breast milk back when I had my daughter I would not doubt that melamine would get into the cow's milk.
    I will look forward to your follow-up post.

  6. The follow-up series, a three-parter, will start tomorrow, December 19th.



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