DUBLIN (AP) — Ireland’s government announced Monday that DNA testing has confirmed that Polish meat offcuts imported into Ireland and labeled as beef actually contain up to 75 percent horsemeat, a discovery made as Ireland’s food-standards scandal forced a second burger manufacturer to shut operations.

Agriculture Minister Simon Coveney said police have joined Ireland’s 3-week-old investigation into why horsemeat has been detected in some Irish-produced burgers and the chief suspect, Poland, has yet to supply any adequate explanation.