GUANGZHOU - A product safety watchdog in southern China has ordered a recall of the cooking oil suspected of containing high doses of a carcinogenic mildew that triggered public concern after it was found in milk products from a popular dairy.

The recall covers cooking oil produced by three companies in Guangdong province -- Fusheng Oil, Manyi Peanut Oil, Mabao Oil -- that contains excessive levels of aflatoxin, officials with the provincial bureau of quality supervision, inspection and quarantine said Thursday.

The companies' storage facilities were closed and licenses revoked as authorities continue the investigation. Their factories were ordered to suspend operations.

It was not immediately known how much of the three companies' tainted products entered the market.

Aflatoxin is produced by a fungus that commonly grows on crops such as grains and peanuts. High levels of the toxin may lead to cancer in some animals.

The mildew recently caught the nation's attention after it was found in high doses in dairy products from the popular Mengniu Dairy Group. An initial investigation showed that the contamination was caused by mildewed feed given to cows in the dairy's plant in southwest Sichuan province.

Mengniu on Monday issued a public apology in an online statement, but insisted that the problem was discovered before the tainted milk could enter the market.