French authorities Tuesday said they had found 57 tonnes of minced lamb that did not conform to European standards at the factory of Spanghero, the firm at the heart of the horsemeat scandal.
The French company sparked a European food alert by allegedly passing off 750 tonnes of horsemeat as beef, which led to its sanitary licence being revoked.
It was subsequently allowed to resume production of minced meat, sausages and ready-to-eat meals. The firm is not allowed to stock frozen meats.
French sanitary inspectors said the contraband lamb, found in February before the sanitary ban was imposed, was furnished by Dutch supplier Draap Trading, which has also been implicated in the horsemeat scandal.
The lamb was made of meat scraped off the bone -- a process banned for meat of European origin since the mad cow disease scandal.
"They don't have the right to import meat from Europe processed under those conditions," said Antoine Leroy, the prosecutor of the southern Carcassone region, where the Spanghero factory is located.
French junior food minister Guillaume Garot said the company had been ordered to withdraw all products made with the meat, including sausages.
Spanghero said it had been duped, adding it had bought the meat in good faith and believed it conformed to its order. It said the meat would be destroyed.
The scandal of horsemeat being passed on as beef has engulfed a string of European countries with millions of ready meals pulled from supermarket shelves.
The row has embroiled major international corporations including Swiss food giant Nestle, which recently recalled lasagnes destined for restaurants in Portugal.