One of Loyd Grossman's curry sauces has had to be withdrawn

Tests by maker Premier Foods found "very low levels" of the dye in the brand of Red Lentil Dhansak sauce.

The Food Standards Agency said the batch - with a best-before date of the end of July 2006 - had been withdrawn.

Sudan I dye-contaminated Worcester sauce caused the recall of hundreds of processed food products last month.

The affected Loyd Grossman jars have been sold in the Waitrose and Sainsbury supermarket chains.

The FSA urged anyone who had previously bought the sauce to return it to their retailer for a refund.

The agency stressed the risk from Sudan 1 at the levels present in the product was very small, but said it would be sensible not to eat it.

'Illegal in food'

The agency said: "The agency was told by Premier Foods today that tests had confirmed the presence of Sudan 1 at very low levels in a batch of the sauce.

"Only this one batch has been found to be contaminated by Sudan 1, a chemical dye which is illegal in food.

"As part of the agency's investigation launched last month into how a number of food products became contaminated with Sudan 1, the agency will be investigating how this latest incident happened."

The Sudan I dye - normally used in shoe polish and other industrial products - was last month found in chilli powder used by Premier to make Crosse and Blackwell Worcester Sauce.

This was then used in hundreds of processed food ranges.