Retailers of dairy products in China have been required to apply for new operating licenses or renew their old ones by the end of July.

Starting in April, dairy retailers should apply for one of two types of licenses. One will allow them to sell baby formula and the other will allow them to sell formula-free products, said the State Administration for Industry and Commerce.

Unlicensed retailers who sell infant formula would be punished, the administration said.

The Chinese Government has tightened regulation of food products in response to the public's safety concerns, which have grown more intense following discoveries of the toxic substance melamine in baby formula in 2008 and, more recently, of illegal additives in pork.