BEIJING -- A Chinese dairy that sold milk powder linked to kidney stones in infants knew it contained a banned chemical weeks before ordering a recall, the health minister said Saturday. One child has died and an official said the number of children sickened had risen to 432. Investigators have detained 19 people and are questioning 78 to find out how melamine was added to milk supplied to Sanlu Group Co., China's biggest milk powder producer, officials said at a news conference. They said some tainted powder was exported to Taiwan but none was sent to other foreign markets. In Taiwan, authorities seized thousands of bags of Chinese milk powder. The incident reflects China's enduring problems with product safety despite a shake-up of its regulatory system after a spate of warnings and recalls about tainted toothpaste, faulty tires and other goods. The biggest group of victims is in China itself, where shoddy or counterfeit products are common. Infants, hospital patients and others have been killed or injured by tainted or fake milk, medicines, liquor and other products. In 2004, more than 200 infants suffered malnutrition and at least 12 died after being fed phony formula with no nutrients. Some 40 companies were found to be making phony formula