Of the leading retailers, Asda and Sainsbury were quick to remove Sudan 1 contaminated lines from the lists of products they were offering online, while Waitrose also had a notice which offered information on the crisis on its online site.

However, Tesco.com has carried no information about the food crisis and The Grocer was able to order a number of contaminated lines on Monday. On delivery the company notified that many of the ordered goods could not be delivered due to the scare.

The FSA added 10 more products to the growing list of Sudan 1-contaminated foods yesterday as the crisis deepens.

The list now stands at 429 products now confirmed to have been contaminated with the illegal food dye.

The new products on the list, which include Tesco Chicken & Vegetable Casserole and Sainsbury Taste the Difference Ultimate Pork Sausages, are in addition to the 57 products that were added to the list on Tuesday.

Among those added to the list yesterday are Worcester sauce flavour crisps from Walkers, Morrisons sausages and Schwartz-branded spice mixes from McCormick and three Aunt Bessie products.

However, it has emerged that companies affected by the contamination crisis may escape fines from the Food Standards Agency (FSA).

The companies, including food manufacturer Premier Foods which supplied the Worcester sauce ingredient responsible for the scare, could avoid the usual fines because the substance entered the food chain before the regulations to test for the dye were enforced.

Routine tests on food quality by supermarkets and manufacturers do not include specific checks for Sudan 1 red dye.

Dr Jon Bell, chief executive of the Food Standards Agency, said: “At the levels present the risk is likely to be very small but it is sensible to avoid eating any more. There is no risk of immediate ill health.”