Eleven people in China have died and about 140 have fallen ill after consuming vinegar stored in plastic barrels that once contained antifreeze, officials and state media said Monday.

Villagers in the remote northwestern region of Xinjiang — home to the mainly Muslim Uighur minority — reported feeling sick after breaking the daily fast for Ramadan on Friday, the local government said in a statement.

Ramadan is the holy month during which Muslims abstain from food, drink and sex from dawn to dusk.

An initial probe found the victims had consumed vinegar from plastic barrels that used to contain antifreeze — a toxic engine coolant — but police were yet to confirm the source of the poisoning, the Xinhua news agency said.

Children as young as six were among the dead and one person remained in a critical condition in hospital, Xinhua added.

In another tainted products scandal, Beijing Tongrentang, a renowned seller of Chinese medicines, said Monday it had recalled its birds' nest products after they were found to contain excessive levels of a cancer-causing chemical.

Birds' nests — which contain the saliva of birds such as swiftlets — are highly prized by Chinese consumers, who believe they can bestow myriad health benefits, from youthful skin to a raised libido.

Last week, Chinese authorities ordered more stringent checks on birds' nest products after official investigations found excessive levels of sodium nitrite, which is commonly used to preserve meats but can also cause cancer.

Xinhua said that the tainted birds' nests had been imported from Malaysia.

Contaminated product scares are common in China despite repeated official pledges to clean up the country's vast food and manufacturing industries and toughen penalties for offenders.

In a recent crackdown on illegal food additives — launched after a wave of contamination scandals — authorities said earlier this month they had arrested around 2,000 people and closed nearly 5,000 businesses.

China launched the campaign in April following a spate of tainted food incidents — included toxic milk, dyed buns and pork found on the market so loaded with bacteria that it reportedly glowed in the dark.