KFC has pulled two chicken dishes off its fast food restaurant menu across China, its owner’s second-most profitable market, after discovering they contained a dye linked to cancer and banned from use in food.

The fried chicken chain removed New Orleans wings and drumstick burgers from the menu at more than 1,000 outlets on Wednesday, and destroyed all tainted products, after discovering a supplier had used the Sudan 1 dye in ingredients, an executive for KFC’s parent, U.S.-based Yum Brands Inc., told Reuters on Thursday.

Sudan 1, an industrial dye used in petrol and shoe polish but banned from food because it heightens the risk of cancer, triggered a food scare across much of Europe last month, causing China to check for its presence in the country, state media said.

“Even though we had asked Yum’s suppliers many times to guarantee their products did not contain Sudan 1, and received written confirmation from them, we regret to say we found it in ingredients,” Yum said in a statement.

“We’re now investigating the supplier in question, to determine its responsibility in using Sudan 1 in ingredients provided.”

The executive would not say which of the company’s suppliers it was investigating.

Yum expected to reinstate the items on its menu within a week, but was unsure how it would affect KFC’s business, said the executive, who declined to be identified.

Health officials told Reuters they had discovered the harmful dye in food items elsewhere around the city. State media reported it had been found in pickles.

“We found Sudan 1 during regular inspections of foodstuffs sold in stores and supermarkets across Shanghai, and have removed affected items from shelves,” an official with the Shanghai Food and Drug Administration said, declining to elaborate or be identified.

Yum said it had discovered the dye on Tuesday.

Britain has taken 428 sauces, soups and ready-made meals off supermarket shelves in the biggest recall in British history since the discovery of Sudan 1 dye in food on Feb. 18.