According to the latest report from the Associated Press, dairy products made in China and contaminated with a chemical called melamine have sickened at least 54,000 babies and killed four. In the wake of the outbreak, first reported two weeks ago, a dozen countries, mostly in Africa and Asia have banned import of Chinese dairy products, including powered milk, baby formula, ice cream and yogurt. New Zealand authorities are now warning its citizens not to eat White Rabbit Creamy Candies; the international supermarket giant Tesco pulled the product from shelves (in groceries from from Britain to Malaysia) after the sweets were found to contain high levels of melamine.

So what is it?

Melamine is a nitrogen-based compound used in commercial and industrial plastics, such as eating utensils and laminates, whiteboard wall paneling, flooring and Formica countertops. According to U.S. Food and Drug Administration (FDA) officials, who investigated melamine contamination in pet food last year, it is also used as a fertilizer in Asia. An estimated 8,500 dogs and cats died of kidney failure after chowing down on melamine laced fare; when large amounts of the chemical are ingested, it causes the formation of kidney stones, as well as the organs' failure.

Chinese food companies use the nitrogen-based compound in wheat flour and other products to make these products appear to have more protein. Normally, proteins are the only source of nitrogen in food, so by looking for that element in tests, one can figure out relative protein concentrations. "Whenever someone looks at nitrogen in food, almost always they are looking at the amount of protein in food," Lora Sporny, a professor of nutrition education at Columbia University in New York, told ScientificAmerican.com last year.

During a press conference held during last year's pet food scandal, FDA official Stephen Sundlof said it was possible that the tainted grub was deliberately spiked with melamine to make  it appear to have higher protein levels. "The motivation would be economic in that you can take a product that is low in protein," he said, "and add a substance that from a chemistry standpoint makes the product appear to have a higher protein content than it does so it can be marketed at the price."

What does melamine do in the body? A Cornell veterinarian told us last year that melamine is not considered to be "a very toxic compound," but can result in kidney stones and kidney failure especially in small animals. Investigators found crystals made up of melamine and its byproducts in the urine and kidneys of in the dogs and cats that were poisoned last year. Because it formed crystals in the body and was not fully dissolved in urine, the melamine gathered in the kidney, gunking up the organ and forming stones. The pets that died suffered acute kidney failure.

Now the same thing appears to be happening to China's tiny tots. Chinese officials claim they have a handle on the problem; there have been at least 18 arrests in the probe and the head of China's quality watchdog group resigned. Nevertheless, parents in China and places where the product is sold are reported to be nervous. The FDA says it's unlikely that any of the tainted products made it to the U.S. but agents were scouting shops in Asian neighborhoods in Los Angeles, New York, San Francisco and Seattle to make sure that none had slipped through to those community shops.

(Photo: iStockphoto/Isabelle Limbach)