A rising number of KFC customers have begun seeking legal advice after the US fast food chain's Beijing restaurants suspended three more items from their menus over fears they may contain the carcinogenic food colouring Sudan I.

Last Saturday, 10 days after the restaurants' New Orleans range was discontinued because of Sudan 1 contamination, the illegal dye was found again in popcorn chicken, spicy chicken wings and hamburgers in one of the company's Beijing outlets.

One customer, a woman surnamed Wu who lives in Chaoyang District, complained, saying it was "annoying that KFC keeps making the same mistake in such a short time."

"I thought of suing the company but gave up the idea because of my ignorance of legal procedures," she said.

But there are some people who are pursuing legal action. Meng Yuxin,an 11-year-old girl from Shenyang in Northeast China's Liaoning Province, has made a claim against KFC for health damages, according to Shenyang Jinbao, a local newspaper.

And according to Beijing lawyer Qiu Baochang, a number of the capital's frequent KFC customers have called for advice on how to safeguard their rights on this issue.

However, Qiu suggested consumers solve the problem through consultation with KFC instead of taking the matter to court.

"Despite high costs, plaintiffs are unlikely to win their case unless they can prove they have had the banned dye at KFC," he said.

One problem for those wishing to take action against the fast food chain is that few customers ask for or keep receipts when eating at KFC while KFC seldom offers receipts.

However, proving they ate at KFC is just the first step.

"If they can prove that their health has been damaged by KFC food, they can surely sue the company for rights infringement," the lawyer added.

"But it is almost impossible to do so because the harm from Sudan I is long term and not immediately apparent."

Representing KFC yesterday, spokesperson Chen Huijing, said the company was confident of being able to handle customers' complaints, adding: "We will obey legal procedures if we receive any complaints."

The fried chicken chain has suffered much from the Sudan I issue, with some suggesting business is down 50 per cent since before the scandal broke.

Editor: Olivia