The presence of horse DNA has been found in some beef burgers sold in UK and Irish supermarkets, a study by the Irish food safety authority revealed.
Of 27 beef burgers tested, 37% tested positive for horse DNA and 85% tested positive for pig DNA. Tesco's Everyday Value Beef Burger was found to be 29.1% horsemeat.
The beef burger products which tested positive for horse DNA were produced by two processing plants (Liffey Meats and Silvercrest Foods) in Ireland and one plant (Dalepak Hambleton) in the UK. Both are sold across the UK.
Traces were found in 10 beef burger products sold in supermarkets across the UK.
The head of the food safety authority of Ireland said the presence of horsemeat "posed no risk to the public" but obviously raised concerns. Professor Alan Reilly said:
The products we have identified as containing horse DNA and/or pig DNA do not pose any food safety risk and consumers should not be worried.
In Ireland, it is not in our culture to eat horsemeat and therefore, we do not expect to find it in a burger. Likewise, for some religious groups or people who abstain from eating pig meat, the presence of traces of pig DNA is unacceptable.
Supermarkets have started to remove the products from their shelves tonight, as investigations get underway.
The Irish Farmers Association said they were very concerned at the findings, and demanded an "urgent investigation".
Ireland's Minister for Agriculture, Simon Coveney, said his department had started their investigations, and stressed that Ireland had "probably" the best food safety system in the world.