BEIJING - Infant food products, in which levels of melamine, a toxic chemical normally used in manufacturing plastics, is higher than 1 milligram per kilogram of food, will be prohibited from sale in China, according to an official regulation issued Wednesday.

In other food products, the maximum tolerable level of melamine is 2.5 mg for per kg of food, said the regulation, issued by Chinese Health Ministry along with other government agencies.

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"Melamine, neither a kind of food material or food additive, is prohibited from being intentionally added into food," said the regulation, which took effect on Wednesday.

Anyone who purposely adds melamine to food would be dealt with according to the law, it added.

However, the regulation also noted very low levels of melamine may enter the food chain naturally from the environment or through products package materials.

Ingestion of melamine over a period of time can cause damage to people's urinary and reproductive systems, lead to kidney stones, and bladder cancer.

In 2008, China's food industry suffered a heavy blow when milk products were found to contain dangerous levels of melamine, which were intentionally added to make milk appear to be protein-rich. The toxic milk killed at least six babies and sickened 300,000 others across the country.