There is no evidence of contamination of horse DNA in Burger King products, a major food group has insisted.
The ABP Food Group, one of Europe's biggest suppliers and processors, suspended all production at one of its plants in Co Monaghan after tests found contamination in frozen burgers.
But it has since insisted that meat for fast-food giant Burger King was produced and stored separately at the plant.
It said: "We would like to reiterate that all Burger King products produced by us are stored separately and manufactured on an independent line. There is no evidence of any contamination of raw material used for the manufacture of any Burger King products."
The group revealed on Thursday night it had stopped work at its Silvercrest Foods plant in Co Monaghan until further notice.
The firm said that, following new results from the Department of Agriculture, it believes the source of the contaminated material is one supplier.
Ten million burgers suspected of containing some levels of horse meat were cleared from several supermarkets' freezers across Ireland and the UK this week and are expected to be destroyed.
Agriculture Minister Simon Coveney revealed that seven samples of raw ingredients were tested, including one sourced from another European country which tested positive. All ingredients in the production of burgers sourced from Irish suppliers tested negative for equine DNA. "Thirteen samples of finished burgers were tested for the presence of equine DNA," said a statement. "Nine have tested positive for traces of equine DNA and another four have tested negative."
The minister and Food Safety Authority of Ireland (FSAI) have arranged to have the positive samples analysed further in Germany with a view to quantifying the percentage of equine DNA present. "The minister and the FSAI have repeated their clear statement that there is no concern from a food safety perspective," the statement added.
Supermarket giant Tesco has placed full-page adverts in a number of UK national newspapers apologising to customers for selling beefburgers containing horse meat. Aldi, Lidl and Iceland have also withdrawn frozen beefburgers from their shelves after they were found to be contaminated with horse meat. Sainsbury's, Asda and the Co-op later withdrew some frozen products but stressed that the move was "purely precautionary" and they had not been found to be selling contaminated food.