THOUSANDS of Halton families could have been eating food contaminated with the illegal red dye Sudan 1 which is believed to cause deadly liver cancer.

And the Food Standards Agency has admitted that 'it is impossible to identify a safe level or quantify the risk' of the carcinogen in the products we eat.

Affected supermarkets and food retailers across Widnes and Runcorn, including Asda, Morrisons, Sainsbury, Kwiksave, Aldi, Iceland, Tesco and Spar, were told at the weekend to remove from sale all products which were listed by the FSA as containing the dye.

Warnings were also issued to McDonald's about a salad dressing and certain product lines from non-supermarketowned brands like Heinz and Coleman's have also been subject to the alert.

The agency also warns that some fast food takeaways and restaurants may have been using Sudan 1- contaminated products in their food and have also ordered their withdrawal.

Sudan 1, which was banned in food after being shown to cause cancer in mice and human liver cells, was found in Premier Foods-manufactured Worcester sauce, a commonly used flavouring by many leading manufacturers and retailers.

The contamination has been tracked to a five-ton consignment of chilli powder made in 2002.

Sudan is a 'Class 3 genotoxin' which caused mutations in human DNA.

Customers were told to check their cupboards for specific products on an FSA 'risk list' which included 350 items at the weekend. But a further 100 products were added on Monday and the FSA said a definitive list of dangerous items would not be available until today.

Reassurance issued by the agency this week included the statement: 'Being exposed to a substance that could contribute to the development of cancer does not necessarily mean that you will develop cancer.'

The guidance also said: 'Because of the widespread use of this Worcester sauce to flavour other foods, we may find further affected products. We will continue to take action to remove these and minimise the risk to consumers.'

Consumers were also assured that: 'There is no risk of immediate ill health.'

A large proportion of the specifically contaminated products were prepackaged ready meals, pies, pizzas, soups and sauces.

Halton council is working to ensure any remaining affected products are removed from sale in the borough and residents are urged to check www.food.gov.uk/sudanlist

Dr Jon Bell, FSA chief executive, said: 'The food companies involved are legally responsible for notifying us, removing the affected products and informing consumers.

'We expect remaining product information to be provided by today.'