The veterinary painkilling drug phenylbutazone – or bute – has been found in Asda Smart Price Corned Beef, the Food Standards Agency has said.
Asda had already withdrawn tens of thousands of its own brand corned beef last month after it was found to contain up to 50 per cent horsemeat.
The supermarket giant removed the £1.54 products from stores across Britain on March 8 – and tests this week showed quantities of horse DNA above trace levels.
Leicestershire County Council found the ingredients of one batch of the 340g tins were half horse, but Leeds-based Asda has insisted it only found levels of up to five per cent.
Asda, which last month said it had carried out more than 700 tests on products during the horsemeat scandal, has had eight products that have been positive for at least traces of horse.
A spokesman for Asda said the chain has ‘taken a belt and braces approach’ to testing for horse DNA and quickly removed any products from its shelves ‘whenever we’ve had any concerns’.
Andrew Rhodes, director of operations at the Food Standards Agency, acknowledged it takes time to test for bute once horsemeat is found in a product.
Speaking on the BBC Radio 4 Today programme, he said: ‘What we have found in this positive test result is a very low level of (bute)… which is only really just above the limit of detection.
‘It’s very unlikely to (do harm). As the chief medical officer has said… it’s extremely rare people have an adverse reaction to phenylbutazone.
‘This is considerably lower than a therapeutic dose and you would have to consume enormous quantities of meat, way more than anyone could physically consume, to get near a therapeutic dose.’
Mr Rhodes said it was important to understand how the product came to be contaminated and how it came to have bute in it.
‘If someone has done something which is illegal, and not taken due measures to prevent that happening, then they can face sanctions,’ he said.
‘But we need to determine exactly what has happened in this case before we can determine whether that will happen or not – which is true of any of the cases we have seen.’