Some of the nation’s biggest retailers including Tesco, Lidl, Aldi and Iceland, have become embroiled in a major meat scandal, after 37% of beef burgers analysed in a sample by the Food Safety Authority of Ireland were found to contain horse DNA, and 85% contained pork DNA.

The burgers were produced by Irish processors Liffey Meats and Silvercrest Foods in Ireland as well as Dalepak Hambleton in the UK.

Of the 10 ‘beef’ burgers which tested positive for traces of horse DNA, Tesco Everyday Value beef burgers contained by far the most, at 29.1% - the next highest scoring product was Oakhurst beef burgers sold at Aldi, which contained 0.3%. 85% of the burgers in the sample tested positive for pig DNA.

Of 31 beef meal products, such as lasagne and cottage pie, also tested by the FSAI, 68% contained pig DNA but none contained horse DNA. 

There was a plausible explanation of the presence of pig DNA in the products testes – because meat from the same animals was tested in the same plants – but there was not a clear explanation for the presence of horse DNA, said FSAI chief executive Professor Alan Reilly. “It is not our culture to eat horse meat and, therefore, we do not expect to find it in a burger.”

For some religious groups who abstained from eating pig meat, the presence of traces of pig DNA was also unacceptable, he added.

Tesco said it was working with the authorities in the UK and Ireland to urgently understand how horse meat made its way into its products. “The safety and quality of our food is of the highest importance to Tesco. We will not tolerate any compromise in the quality of the food we sell,” the retailer’s technical director, ex-FSA CEO Tim Smith, said in a statement. The presence of illegal meat in its products was extremely serious, he added. 

Of the 10 burgers that tested positive for horse DNA, three were sold by Lidl, two by Tesco, two by Iceland, two by Dunnes Stores and one was sold by Aldi. Those that tested positive for pork DNA were sold by Tesco, Lidl, Aldi, Iceland, Supervalu and Dunnes Stores as well as Aldi, Spar, Centra, FXB Butchers and Superquinn.