Supermarket Asda has announced that it is recalling its tinned Smart Price corned beef after DNA testing identified low levels of horse medication bute.

Last month, the grocer withdrew its 340g tins of the product after testing revealed that it contained horse DNA and tests to further batches gave a positive result for the veterinary drug.

Asda said in a statement: “In March 2013 we withdrew tinned Smart Price Corned Beef (340g) after receiving a positive test for horse DNA above the one per cent trace level set by the Food Standards Agency (FSA).

“Today, 9th April 2013, tests on further batches have shown a positive result for very low levels of horse medication called phenylbutazone, also known as bute, at 4 parts per billion.

“The FSA has reassured us that the quantities we‘ve found pose a low risk to human health. Although there is a very low health risk, we are recalling this product.”

Customers have been warned not to eat the product and those who have it at home can return the item to stores for a full refund.

As a precautionary measure, the chain is also recalling 340g tins of its Chosen By You corned beef as it is made in the same factory as its Smart Price product, reiterating its commitment remove items “whenever we have the smallest concerns”.

Ade McKeon, the Asda director responsible for the quality of all own branded products, said: “I know our customers will be just as concerned about this news as we are.

“Even at such a low level, it is totally unacceptable.

“I can reassure our customers that we are working closely with the FSA and our suppliers to deliver a wide ranging and rigorous programme of testing, to be sure that the products we sell are exactly what it says on the label.”