This morning’s post from Molecule of the Day reminds me to ask “cyanuric acid question.”
With the recent adulterations with melamine of Chinese milk and milk products (like White Rabbit chocolates) and foods with other milk-derived ingredients, we wonder if we will ultimately hear that a compound from fertilizer, cyanuric acid, is part of the mix.
Melamine is a cheap chemical that gives a false positive in typical protein assays; therefore, it can be used to make food appear to contain more protein than it actually does. You’ll often hear of cyanuric acid being referred to as a pool chemical as it helps stabilize chlorine donors in the sun, but it is often used as a nitrogen source in fertilizers. It tends to concentration in wheat gluten and that’s how it may end up together with melamine in some food products.
What is not mentioned too often in the press is that melamine alone is remarkably safe – an FDA report notes that the oral dose required to kill 50% of test rats, or LD50, is 3161 mg/kg body weight – an astronomical dose. Cyanuric acid is even less toxic, with a reported LD50 of 7700 mg/kg. While the LD50 is a single-dose, acute toxicity test, even prolonged daily dosing of either compound is relatively safe with a no-observed-adverse-effect-level (known as NOAEL) of 63 mg/kg daily for 13 weeks in rats.
So, while you don’t want to ingest either compound unnecessarily, they become much more problematic when combined. Melamine and cyanuric acid polymerize and precipitate out in the kidney, causing renal failure and death. In May 2007, I posted on one of the best journalism stories on the topic, by David Brown at the Washington Post, who wrote on the pet food contamination episodes then.
Molecule of the Day is a great resource for learning more about the chemistry of these compounds, complete with chemical structures – in general, MoTD is a great, quick, content-rich and enjoyable read every single post.
See “Melamine and Cyanuric Acid Chemistry Lesson” for our more detailed discussion of melamine and cyanuric acid.