A Fine Gael MEP is calling for the companies involved in the horse meat scandal to explain why they use imported beef.
Yesterday the source of the contaminated meat product was identified as having been imported by Co Monaghan meat traders McAdams Foods.
Gardaí and a team of Department of Agriculture investigators raided the home of factory owner Martin McAdam. They seized records and electronic material.
His company imported Polish beef product, found to contain up to 80% horse DNA.
Speaking at the European Parliament in Strasbourg, Mairead McGuinness has questioned why food companies are importing meat products for beef burgers when there is already a plentiful supply in Ireland.
"Ireland is a major beef producer. The question that has to be asked is why do we need to import any additives for beefburgers when we are a massive exporters of beef products?" she said.
"I think the companies need to answer that question. We've heard very little from the companies themselves."