Four babies were killed and at least 54,000 babies made ill on the mainland, official figures show, but the toll has not been updated for a few days.

The samples were randomly chosen from 19 big cities including Beijing, Shanghai, Tianjin and Chongqing , it said, adding they came from major milk production bases spanning 21 provinces and regions such as Hebei , Inner Mongolia , Jiangsu , and Beijing.

Since September 24, the quality watchdog has tested 763 batches of milk products from 55 companies and all were free of melamine, it added.

The watchdog also urged all supermarkets and shopping malls to make public a list of the companies and products that pass quality checks to ensure a sufficient supply of dairy products.

The latest test results came as authorities continued efforts to restore consumer confidence in a dairy industry tarnished by sales of tainted products.

Premier Wen Jiabao yesterday visited children at a hospital in Tianjin waiting for tests and a supermarket, where he called for stringent tests on milk.

In response to the crisis, mainland hospitals have established specialist teams to randomly check babies for kidney stones.

In Hong Kong, the Centre for Health Protection said yesterday there had been no new reports of kidney problems related to the consumption of melamine-tainted milk products.

The centre said results of melamine tests on dairy products found all 77 samples - including products made in Hong Kong, on the mainland and overseas - were safe.

A centre spokesman said it would continue testing dairy products.

Public concern over food safety has continued however, with parents in Hong Kong besieging hospitals to have their children examined.