Manufacturers of baby formula in China are required to check each batch of raw materials and their finished products for the toxic chemical melamine, according to a new draft regulation.

The draft regulation, which details the requirements for producing baby formula milk powder, was released over the weekend by the General Administration of Quality Supervision, Inspection and Quarantine (AQSIQ), the country's top quality watchdog, to solicit public opinion.

A public hearing on the draft regulation is due to be held on Wednesday. Members of the public can apply to the administration before noon on Monday for up to 10 seats at the hearing, according to a notice on the AQSIQ's website.

The draft regulation stipulates that raw materials and supplements for the production of baby milk formula must meet the national or industry standards, and the use of non-dairy animal protein and other inedible materials are strictly banned.

Baby formula producers are required to conduct melamine tests on each batch of raw materials and each batch of their finished products. Test reports must be kept for at least two years, according to the draft.

Each enterprise is required to have at least two inspectors who are capable of independently conducting the safety tests.

Producers are permitted to purchase raw milk only from licensed dairies and quality reports should accompany each batch of the raw milk, the draft stipulates.

The draft regulation is widely seen as a measure to further tighten safety procedures involved in the production of baby formula after melamine-tainted milk powder killed at least six infants and sickened about 300,000 children in China in 2008.

In the incident, milk powder from 22 domestic dairy plants was found to contain excessive melamine, an industrial chemical that is added to watered-down milk to boost its protein levels during quality tests.

Wang Dingmian, former chairman of the Guangdong Provincial Dairy Association, said many large-scale manufacturers had already started melamine tests on all batches of raw materials they purchased following the 2008 scandal.

"For the big enterprises, it's much cheaper to do the tests than to take the risks," he said.

Once the proposed regulation takes effect, the tests will become compulsory for all manufacturers.