The Netherlands' food watchdog on Wednesday asked hundreds of companies across Europe, supplied by a Dutch wholesaler suspected of mixing beef and horsemeat, to check 50,000 tonnes of suspect meat.
The organisation sent a letter to 130 Dutch companies who were supplied with possible horse-contaminated beef from the Selten company asking them to "take it off the market as a precautionary measure" and "verify all products". Around 370 companies across Europe could also be affected, the organisation said.
"The companies have possibly already processed the meat and sold it," the government's NVWA food and consumer watchdog said in a statement.
"We estimate it's about 50,000 tonnes of meat," it added.
NVWA spokeswoman Esther Filon told AFP that the meat was supplied between January 2011 and February 2013 across Europe, meaning that much of it has already been consumed.
The companies have two weeks to report back to the NVWA, who has also informed health authorities in France, Germany and Spain.
Dutch officials in February raided the Selten meat processing plant in the south of the Netherlands on suspicion that it was mixing horsemeat with beef and selling it as pure beef.
Since the problem was first discovered in Ireland in January, governments have scrambled to figure out how and where the mislabelling of meat happened in the sprawling chain of production spanning abattoirs and meat suppliers across Europe.