Anglo Beef Processors has suspended all production at its Silvercrest site in Ireland, one of the meat processing plants implicated in the horse meat contamination scandal.

The move comes after new laboratory tests carried out by Ireland’s department of agriculture, food and the marine this week – the results of which were released last night – once again uncovered horse DNA in burgers produced at the plant.

ABP said any products produced at the site during this week would not be released to the public. Staff will continue to be paid while investigations into the contamination incident, which was first uncovered through tests on burgers carried out by the Food Safety Authority of Ireland, continue.

ABP said its investigations had to date focused on two third-party suppliers from the EU, and it believed it had managed to trace the source of the contamination to one of those suppliers. “However, because equine DNA has been found in finished products tested this week, we have decided that the responsible course of action is to suspend all production at the Silvercrest plant in County Monaghan with immediate effect,” the company said in a statement.

Announcing the results of its latest tests tonight, Ireland’s department of agriculture said the presence of horse DNA was detected in some burgers produced at Silvercrest between 3 and 14 January as well as some raw ingredients.

The department said: “Seven samples of raw ingredients were tested, one of which, sourced from another [EU] member state, 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. Nine have tested positive for traces of equine DNA and another four have tested negative.”

It added investigations would continue, and all raw ingredients used in the production of burgers would be examined. “This, together with the further laboratory tests being conducted in Germany, should give greater clarity to the source of the original problem,” the department said. “The focus of the investigation is now to establish a common ingredient used in the manufacture of burgers in all three plants and from where it was sourced.”

It also reiterated its advice that the test results did not indicate the burgers were unsafe from a food safety perspective.