Asda has recalled all date codes of its 340g Smart Price tins of corned beef, after some of the products tested positive for the veterinary drug phenylbutazone.

Asda withdrew the tins from shelves on 8 March because tests showed samples of the product contained more than 1% horse DNA. It is now asking the public not to consume any tins that were bought prior to the withdrawal and return them to Asda stores for a full refund. The tins in question were manufactured in France by French manufacturer Toupnot.

Phenylbutazone – also known as bute – is not allowed in the food chain in any quantity as the drug can be potentially hazardous to human health. However, Asda and the Food Standards Agency stressed the quantities found in the Asda corned beef were “very low” – four parts per billion – and “even if people have eaten products which contain contaminated horsemeat, the risk of damage to health is very low”.

In a statement on its website, Asda said: “We have taken an extremely cautious approach since the very beginning and have carried out more than 700 tests, moving swiftly to remove any products from our shelves whenever we’ve had the smallest concerns. Our commitment to you is to continue to test our products regularly and update you with the very latest news as soon as we can.”

The FSA is testing any products found to contain horse DNA for bute. This is the first time a processed meat product in the UK has come back positive for the drug. Bute was previously found in horse carcases exported from the UK to France and the Netherlands, at much higher levels than in the Asda products, the FSA said.

Asda has also recalled all tins of its Chosen By You corned beef as a precaution because it is made in the same factory as the Smart Choice corned beef, but said the Chosen By You product had not tested positive for bute.

In early March, Portuguese consumer association Deco said some meatballs and burgers sold in Portugal had tested positive for bute, while authorities in Switzerland found bute in horsemeat imported from Canada.

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