China imposed strict limits of melamine levels tolerable in food products, according to an official regulation issued on Wednesday by the Ministry of Health, Xinhua News Agency reported.

The maximum level of melamine in infant food products should be no more than 1 milligram per kilogram of food and that in other food products should be no more than 2.5 mg per kg of food, said the regulation.

Melamine is prohibited from being intentionally added into food and anyone found intentionally adding melamine to food would face penalty according to law.

However, very low levels of melamine, which will do no harm to the public health, may enter the food chain naturally from the environment or through product package materials, said the regulation.

Melamine is a toxic chemical normally used in the production of plastics, but it can also make milk appear to be protein rich. In 2008, milk with dangerous levels of melamine killed at least six babies and sickened 300,000 others across the country.