The Food Standards Agency has said that the vast majority of food that was contaminated with Sudan 1 has been removed from shops by the companies concerned.

This was in response to the deadline given to food companies to meet their legal responsibility to withdraw the affected products from sale.

The FSA also reported earlier this week that it would be conducting the largest ever investigation of its kind in the UK into the supply of foods contaminated with the illegal dye Sudan 1.

Any companies that fail to ensure that food placed on the market is safe and fit for human consumption can face prosecution under the General Food Regulations, but local authorities, not the FSA, are responsible for taking forward any prosecution.

Therefore, the FSA is coordinating with five local authorities in areas where the key companies in the chain of supply are based, in order to carry out further inspections of companies and factories allegedly involved in the supply of these foods.

The five local authorities include: Essex County Council, Lincolnshire County Council, South Holland District Council, Rochdale District Council and Basildon District Council.

David Statham, the FSA’s director of enforcement, said: “This is a major investigation. Local authorities across the country have visited a number of premises to look at records and take samples. Our advice to local authorities is that they will need to consider enforcement action on the basis of the evidence they collect. We will review the position with local authorities when the collection of evidence is complete. That may take some time.”

Meanwhile, the FSA added 146 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 include Safeway's red pesto and Asda's Char Sui Pork.

Among those added to the list earlier this week 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.”