Polish authorities have found signs of horse DNA in beef stored at three storage facilities.
Officials in Ireland, Britain, Germany, Italy and the Czech Republic have reported that products such as burgers and lasagne contained horse meat that originated from facilities in Poland.
Poland's General Veterinary Inspectorate said in a statement last night that it found three tainted samples from 121 tested, with 80 more to be examined.
Polish officials had previously said they found no signs of horse meat at any abattoirs tested.
Tests in Ireland last month revealed some beef products contained horse meat, triggering recalls of ready-made meals in several countries.
Poland exports 330,000 tonnes of beef products annually, or more than three-quarters of its total production, mainly to other European Union members.
Meanwhile, a meat company at the centre of a Department of Agriculture investigation has had its EU approval restored.
The department had said B&F Meats had exported some horse meat labelled as beef to the Czech Republic via a UK trader.
In a statement, B&F Meats of Carrick-on-Suir said it is satisfied that its records would clearly show that it had not at any stage misrepresented the nature of its products.
The Department of Agriculture has said the company has now complied with all the requirements of a compliance notice and the department is not in a position to prevent it resuming business.