Beijing (AsiaNews) – So far this year, 59 kidney stone cases in infants (from 0 to two years) have been reported. One case has led to an inquiry into a baby formula sold by Sanlu, the biggest milk powder producer on the mainland.

Last night the Shijiazhuang-based group announced that it was recalling all of its infant milk powder products made before August 6. It estimated some 700 tonnes of the good were on the market. They contained traces of tripolycyanamide, a substance which can cause kidney stones and is used to make plastics and fertiliser.

The company statement did not say whether the problem was due to sabotage or contamination during the manufacturing process.

Health authorities said they would investigate the matter. So far cases of kidney stones and renal failure in babies were recorded in Gansu, but other cases have been registered in Shaanxi, Ningxia, Henan, Shandong, Hunan, Hubei, Jiangsu, Anhui and Hubei in the past two months. Most of babies lived in rural areas and all had been fed Sanlu milk powder.

There were no such cases last year or in 2006.

Patients all suffered from rare acute renal shutdown, an enlarged kidney and vomiting.

Food and drug poisoning is nothing new in China. The current scare is already being compared to the milk-powder tragedy of four years ago in Anhui province, when 13 infants died after being fed a substandard product, along with four other deaths in Chongqing and Hubei. Another 170 suffered serious developmental abnormalities.

In China demand for powdered milk is up. Overworked or migrant mothers have had to find an alternative or supplement to breastfeeding.

A recent survey by the China Consumers' Association of 15,000 mothers of babies under six months found that only just over half fed with breast milk exclusively. More than 32 per cent said it was impossible to breastfeed because of their work. But more than 14 per cent stopped breastfeeding because they thought powdered formula was more convenient and nutritious.

Last March after scandals involving poisoning and rampant corruption, the government decided to set up a super Ministry of Health that took over the State Food and Drug Administration.