China, where 13 babies died in 2004 after being fed fake milk powder, has sent back 100 tonnes of powdered milk made in the United States because it contained excess levels of nitrites, Xinhua news agency has said.
The powder, which was imported between July 10 and August 10 by a Chinese company, was worth US$ 200 000 and contained almost twice as many nitrates as Chinese law permits.
The milk has been sent back to the United States and China's food safety watchdog has stepped up inspections of imported milk powder to ensure consumer safety.
China has been struggling to control a rise in the number of food-related health scares.
At least 70 people in Beijing have contracted meningitis from eating raw or uncooked snails, prompting authorities to ban their sale in the city and fine people who continue their sale.
In 2004, at least 13 babies died of malnutrition and nearly 200 fell ill after they were fed with fake milk powder made in the eastern province of Anhui.