Investigations are under way into the discovery of traces of horse DNA in beef burgers for sale in Ireland and Britain.

The Food Safety Authority has said there was no risk to health from the products - which were on sale in Aldi, Dunnes, Iceland, Lidl, and Tesco stores.

All batches have been removed from supermarket shelves.

The burgers were produced at two Irish processing plants, Liffey Meats and Silvercrest Foods, and at one plant in North Yorkshire.

Bord Bia's chief executive said the agency has begun work to reassure and inform customers about the discovery of horse meat in Irish processed beef burgers.

Bord Bia is responsible for the marketing and promotion of Irish food world-wide.

Aidan Cotter described the discovery as deeply disappointing and said it was important to get to the bottom of it. However, he stressed that Ireland's food industry is subject to some of the most rigourous controls in the world, and believed this would reassure customers.

He said that 90% of Irish meat exports to Europe are unprocessed 100% pure fresh Irish beef.

Mr Cotter said Irish processed beef products are primarily consumed in the UK and Ireland, with very little of it exported to Continental Europe.

Meanwhile, the chief executive of ABP Food Group, the parent company of Silvercrest - one of the companies at the centre of the horsemeat controversy - said the source of the contamination was a beef based product bought from third party suppliers outside Ireland.

He said the company's investigation was focussed on two suppliers in particularly.

"We don't buy any horsemeat. And the product in question from the suppliers that is being examined at the moment is going through a review process, an investigation process. It will take us two or three days to get to the bottom of it,'' Paul Finnerty said.

"What we had understood we were buying is not what was actually received,'' he added.

He said "substantial testing" was being carried out, and the product has been segregated within the production plant, where manufacturing is continuing.

Mr Finnerty said the company is "extremely disappointed" with what has happened and is working intensively with its customers. He said the company has asked retailers to withdraw 10 million burgers from the market on the basis of a sample from one batch of burgers. He said the affected burgers represent less than 5% of the company's overall business.