The UK's Food Standards Agency is advising people not to eat certain batches of fresh organic free range chicken found to contain traces of a nitrofuran, a banned veterinary medicine. 

The affected products include both whole birds and chicken pieces, which are sold under the brand names Moy Park, Tesco, Waitrose and Morrisons. Up to 23 tonnes of affected chicken has been distributed across the UK.

The FSA said that all the affected products are past their use by dates, so no-one should have any left in their fridge. They are no longer on sale in supermarkets. However, anyone who has frozen any of this chicken should not eat it.

Under EU law it is illegal to use nitrofurans in food-producing animals because it could increase people's risk of getting cancer. The health risk from eating an affected chicken is low, because concerns relate to long-term exposure to these drugs. However, the FSA said it is taking action because it believes it is not acceptable that traces of these drugs are present in food, as they have been banned within Europe since 1995.

The problem came to light during routine tests, carried out by the Department of Agriculture and Rural Development's (DARD) Veterinary Science Division, as part of the UK's surveillance programme for veterinary medicines. The chickens came from a Northern Ireland farm. The chicken was supplied to supermarkets across the UK by Moy Park, a food processing company in Northern Ireland.