US pork producer Smithfield Foods Inc has shut one of its Polish meatpacking plants, after local media showed its employees scraping mould off sausages and sending them back to retailers, the Reuters news agency reports.

Late last week daily newspaper Rzeczpospolita and television channel TVN caught workers at the Constar plant on hidden cameras, debating whether expired products sent back by stores should be thrown out or cleaned up and sent out again, the agency said.

"The director (of Constar) has been suspended from performing his duties...and production has been halted until the matter is cleared up," said Lidia Zalewska, a spokeswoman for Smithfield's Polish unit Animex, which owns Constar.

She added that in addition to an investigation by government food safety inspectors, the company had launched an internal audit at Constar.

The European Union, which Poland joined last year, is awaiting the results of the Polish investigation before deciding whether to take any action, according to Rzeczpospolita.

Other Animex producers were functioning normally and the company had not undertaken any special measures outside Constar in response to the matter, Zalewska said.