"It would be like if you had a million grains of sand and they were all white, and you had two or three that were black, that's kind of the magnitude," said Stephen Sundlof, director of the FDA's food safety program.
The FDA guideline is meant to help federal and state investigators checking for contaminated foods from China at ports of entry and in Asian community groceries around the country. "We are trying to identify products that have levels we are really concerned about, rather than trying to find the last molecule," said Sundlof.
For example, melamine levels in imported Chinese candies recalled last week in California were as high as 520 parts per million, about 200 times greater than the level set on Friday by the FDA for "tolerable" risk.
In China, melamine-tainted formula has sickened more than 54,000 children, mainly with kidney problems, and is being blamed for the deaths of at least four. The industrial chemical has also turned up in products sold across Asia, ranging from candies, to chocolates, to coffee drinks, all of which used dairy ingredients from China.
In the U.S., White Rabbit candies from China were recalled after authorities in California and Connecticut found melamine. And Friday, a New Jersey company announced it was recalling a yogurt-type drink from China, 'Blue Cat Flavor Drink,' after FDA testing found melamine.
No illnesses have been reported in the U.S., but authorities are checking for any telltale increase in reports of kidney problems.
The FDA says infant formula sold here is safe, because manufacturers do not use any ingredients from China. But officials expect more melamine recalls as they continue to test products in ethnic markets.
FDA officials stressed that the melamine risk assessment issued Friday does not mean U.S. authorities will condone foods deliberately spiked with the chemical.
The 2.5 parts-per-million standard is meant to address situations in which the chemical accidentally comes into contact with food. For example, plastic food processing equipment may have been made using melamine, and some of the chemical might find its way into food.
Infant formula sold to U.S. consumers must be completely free of melamine. "There is too much uncertainty to set a level in infant formula and rule out any public health concern," the FDA said.
In China, unscrupulous suppliers appear to have been adding melamine to make watered-down milk seem protein-rich in quality-control tests. That's because melamine is high in nitrogen, as is protein.
Melamine first came to the attention of U.S. consumers last year, when it touched off a massive pet food recall. Chinese suppliers of bulk pet food ingredients were found to have been adding the chemical to artificially boost the protein readings of their products. Thousands of pets here were sickened, and hundreds are believed to have died.
Melamine is harmful to the kidneys. It can cause kidney stones as the body tries to eliminate it, and in extreme cases, life-threatening kidney failure.
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