Sausages are one of the affected items

The Food Standards Agency announced on Friday that 359 products containing the illegal Sudan 1 dye had been withdrawn.

But the BBC has learned that since then many more contaminated food products have been identified.

The dye, found in chilli powder used to make Worcester sauce, was then used as an ingredient in other products.

Stores across the country have been working to clear their shelves of the suspect items.

But some smaller corner shops say they are still not getting enough information to help them identify the products.

The FSA has also been criticised for waiting nearly two weeks to make a public announcement after being notified of a potential problem by supplier Premier Foods on 7 February.

The total cost of the recall is estimated to be around �100m.

Shadow health minister Chris Grayling has written to the Melanie Johnson, the Public Health Minister, arguing that the FSA has become "too large and ill-focused."

Working together

RECALLED FOOD Food Standards Agency: List of affected products, 18 Feb Updates to list, 21 Feb Further updates, 21 Feb Most computers will open PDF documents automatically, but you may need to download Adobe Acrobat Reader. Download the reader here Q&A: Sudan 1 What is the health risk?

Dr Jon Bell, an FSA spokesman, said the agency was liaising with manufacturers, retailers and local inspection teams to ensure contaminated products were removed from sale as quickly as possible.

"We are still collecting information. Over 300 manufacturers and retailers were involved in this recall, and it does take time to track down every last product.

"We are making it quite clear to all concerned that we expect them to have withdrawn all the products from the shelves by Thursday at the latest."

Dr Bell stressed the there was no immediate risk to health - and the overall risk was small.

But he added: "It is not sensible for people to be continuing to eat these products."

Sudan 1 is normally used as a colouring in solvents, oils, waxes, petrol, and shoe and floor polish.

Refund

TIMELINE 7 Feb: FSA informed by Premier Foods one of their products exported to Italy had tested positive for Sudan 1 10 Feb: Tests confirmed contamination of two products 11 Feb: Premier informed FSA problem was more widespread 14 Feb: FSA receives list of more than 200 customers 15 Feb: FSA meeting with representatives of the food industry representatives 17 Feb: FSA receives information on 359 contaminated products 18 Feb: Public announcement

Customers who find any of the soups, sauces and ready-meals in their cupboards or freezers are advised to return the packaging to their retailer for a refund.

Kate Ison, spokeswoman for the British Retail Consortium, said small convenience stores as well as large supermarket chains had pulled products from their shelves.

"I think it is going to be an on-going process because the FSA have quite clearly said that they will keep up-dating their list if products come up which are potentially affected," she said.

In his letter, Mr Grayling said the FSA had spent too much time focusing on health education.

"When one sees the FSA apparently reacting slowly to a problem like that experienced in the past few days, it is difficult to escape the conclusion that it has taken its eye of the ball," he said.

HAVE YOUR SAY It's not nearly as serious as the scaremongers would have you believe Peter, Nottingham Send us your comments

The affected products are either ready-made meals, sauces or other processed foods.

They include own-label lines from Asda, Waitrose, Morrisons, Sainsbury's, Tesco, Somerfield, Iceland, the Co-op and Marks and Spencer.

It extends to a low-fat Caesar dressing made for burger chain McDonald's.