Koen Verheijden / AFP - Getty Images file

Employees at Willy Selten Meat Wholesale in Oss, Netherlands, work on Feb. 15 after Dutch officials raided the factory believed to be mixing horse and beef and selling it as pure beef. On Wednesday, the Dutch government ordered it and another company to withdraw 55,000 tons of meat from the market.

AMSTERDAM -- Dutch food safety authorities have ordered the Europe-wide withdrawal of 55,000 tons of beef from sale over concerns that it might contain horse.

The Netherlands Food and Consumer Product Safety Authority said in a statement on Wednesday it had told more than 130 Dutch processing firms to trace the meat, all of which had come from two Dutch wholesalers, and withdraw it.

The wholesalers involved were Wiljo Import and Export and Willy Selten Meat Wholesale.

"It might contain traces of horse meat, but we don't know for certain at the moment if this is the case," said a spokeswoman for the authority.

Inspectors examining Willy Selten's records had found that the origin of the meat it supplied was unclear, the authority said.

The authority said that meant it was impossible to confirm that slaughterhouses had been acting according to procedure. It said it did not know where the meat had ended up, but it could have been used in frozen products.

"The buyers have probably already processed the meat and sold it on," it said in a statement.

"They, in turn, are obliged to inform their own customers."

About 370 companies in other European countries have bought the meat, and the Dutch food authority has warned foreign counterparts about the recall via a European rapid alert system, it said.

It said there was no immediate suggestion of any danger to human health.

In January, tests in Ireland revealed that some beef products contained horse, triggering recalls of ready-made meals in several countries and damaging confidence in Europe's vast and complex food industry.

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LONDON -- Britain's food regulator said horse meat had been found in beef products at Taco Bell fast food outlets, the first time it has been discovered on sale in British restaurants since the scandal broke in January.

The Food Standards Agency said Friday that it had conducted 1,797 tests over the past seven days, over 99 percent of which had come back negative for horse meat levels at or above 1 percent.

However, four tests were positive, it said. These included Birds Eye ready meals and Brakes skewers, already withdrawn from sale.

It added that no tests to date on samples containing horse DNA had found the veterinary medicine phenylbutazone, or "bute."

Tex-Mex fast-food chain Taco Bell, owned by U.S. firm Yum Brands Inc., has three outlets in the U.K.

"Some batches of ground beef supplied to us from one supplier in Europe tested positive for horse meat," Taco Bell U.K. said in a statement.

"We immediately withdrew ground beef from sale in our restaurants, discontinued purchase of that meat, and contacted the Food Standards Agency with this information," it added.

The news is awkward timing for Yum, which on Monday said it was moving to tighten food safety and reverse a sharp drop in business at its KFC restaurants in China after a scare over contaminated chicken.

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Six horses slaughtered in the U.K. that tested positive for a potentially harmful drug were exported to France and may have entered the human food chain, Britain's Food Standards Agency said Thursday.

Phenylbutazone, commonly known as bute, is an anti-inflammatory painkiller for sporting horses but is banned for animals intended for human consumption.

Britain's food regulator said  it was gathering information on the six carcasses sent to France and will work with the French authorities to trace them.

The FSA said it checked 206 horse carcasses between Jan. 30 and Feb. 7. Of these, eight tested positive for the drug.

It said the six sent to France were slaughtered by a firm in Taunton, western England. The remaining two did not leave the slaughterhouse in Nantwich, north west England, and have now been disposed of.

The FSA introduced 100 percent testing of horse carcasses on Jan. 30 in response to the growing horse scandal.

Growing concern
The issue first came to light on Jan. 15 when routine tests by Irish authorities discovered horsemeat in beef burgers made by firms in Ireland and Britain and sold in supermarket chains including Tesco, Britain's biggest retailer.

Concern grew last week when the British unit of frozen foods group Findus began recalling its beef lasagne on advice from its French supplier, Comigel, after tests showed concentrations of horsemeat ranging from 60 to 100 percent.

Meanwhile in France, an investigation into how horsemeat found its way into prepared meals in Europe discovered that a French processing company called Spanghero sold what could have been horsemeat as beef, officials said Thursday.

"It would seem that the first agent in this chain to label the meat 'beef' was indeed Spanghero," Consumer Affairs Minister Benoit Hamon told a news conference of the company based in the southwestern town of Castelnaudry.

"The investigation shows Spanghero knew the meat labeled as beef could be horse. There was a strong suspicion," he said, arguing that Spanghero could also not have failed to notice that the meat in question was much cheaper than beef.

In an emailed statement, Spanghero denied the accusations and said it firmly believed that what it was selling was beef.

Agriculture Minister Stephane Le Foll said the government was considering withdrawing Spanghero's operating license.

The investigation found the company had generated a profit of 550,000 euros ($733,800) over six months by selling cheap horsemeat as beef, Hamon said.

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