China, trying to assuage a growing number of countries that are banning its imports, has adopted its first rules governing levels of an industrial chemical at the center of the tainted milk scandal.
The government has been struggling to deal with festering health and public relations issues since the crisis erupted last month. China's food exports have increasingly suffered, with more nations issuing import bans.
The melamine contamination has been blamed in the deaths of four babies and for sickening more than 54,000 children.
Dairy suppliers have been accused of adding melamine to watered-down milk to make the product appear rich in protein. There had been no previous standards.
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Under guidelines adopted Wednesday, melamine limits considered safe are set at one part per million for infant formula and 2.5 parts per million for liquid milk, milk powder and food products that contain more than 15 percent milk.
Melamine, used in products including plastics, paint and adhesives, can lead to kidney stones and possibly life-threatening kidney failure.
Wang Xuening, a Health Ministry official, said any items containing higher levels will be “prohibited from sale.”
Wang acknowledged that small amounts of melamine can leech from the environment and packaging into milk and other foods but said that deliberate tainting is explicitly forbidden.
“Melamine cannot be used as an ingredient or additive in food products,” Wang said. “For those who add melamine into food products, their legal responsibility will be investigated.”
Levels of melamine discovered in batches of milk powder recently registered as much as 6,196 parts per million.
Guidelines in Hong Kong and New Zealand say melamine in food products is considered safe at 2.5 parts per million or less, though Hong Kong has lowered the level for children under 3 and pregnant or lactating women to one part per million.
In the U.S., the Food and Drug Administration says its experts have concluded that eating 2.5 parts per million of melamine – a minuscule amount – would not raise health risks, even if a person ate food every day that was laced with it.
Even before the uproar over contaminated milk, China's manufacturing industry had been under intense scrutiny after melamine and other industrial toxins were found last year in exports ranging from toothpaste to a pet food ingredient.
The current crisis has prompted the government to fire local and even high-level officials for negligence, while repeating earlier promises to raise product safety standards.