China's Ministry of Health (MOH) is conducting a nationwide investigation into a new case in which dozens of infants have reportedly fallen ill after taking Dumex milk food, China Daily reported on Thursday.

The country's health experts are trying to find out the epidemiological reason behind the increasing number of kidney stone cases among the children.

Although the General Administration of Quality Supervision, Inspection and Quarantine said Tuesday that the company's baby food was free of melamine, parents are not happy with the official test result.

Jiang Yalin, the mother of a 20-month-old kid suffering from a kidney ailment, has organized a group of parents in Kaili of southwest Guizhou Province to seek compensation from baby milk food firms.

Ma Yangchen with the ministry's press office said that the ministry has asked local health administrations to carry out epidemiological research on kidney ailments among children.

A survey conducted in northwest Gansu Province recently showed that 5.6 percent of the kids with kidney ailments had never taken any milk powder.

Jiang said local health experts on Wednesday asked the families of the ailing kids about their lifestyle and living environment, and took samples from the unused Dumex milk powder.

Lin Zheng, lawyer of Jiang and six other parents, said they wanted a third party to test the Dumex milk powder again.

"We still don't have enough evidence to prove the kidney ailments are directly caused by the milk powder," Lin said.

(Xinhua News Agency February 19, 2009)