The French firm at the heart of Europe's food crisis vowed Friday to prove its innocence, as two more countries confirmed their supermarkets had sold ready-to-eat "beef" meals containing horsemeat.
Meat-processing firm Spanghero again insisted it was not responsible for the mislabelling that has seen supermarket chains across the continent pull millions of suspect food products from their shelves.
"I don't know who is behind this, but it is not us," Spanghero boss Barthelemy Aguerre told Europe 1 radio, adding that the accusations were putting his 300 workers' jobs on the line. "I will prove our innocence."
The scandal has left governments scrambling to figure out how and where the mislabelling of the meat happened in the sprawling chain of production spanning abattoirs and meat suppliers across Europe.
The French government threw some light on that question on Thursday when it presented the results of its initial investigation that pinned much of the blame on Spanghero, which operates from the southwestern town of Castelnaudary.
It said the firm knowingly sold 750 tonnes of horsemeat mislabelled as beef over a period of six months, 500 tonnes of which were sent to French firm Comigel, which makes frozen meals at its Tavola subisidiary in Luxembourg.
That meat was used to make 4.5 million products that were sold by Comigel to 28 different companies in 13 European countries, said the findings by the DGCCRF anti-fraud office.
Consumer Affairs Minister Benoit Hamon said Spanghero would be prosecuted and its licence to handle meat suspended pending inspections of its premises by a team of veterinarians.
Food safety experts from across the European Union were meeting in Brussels on Friday to confirm measures for large-scale testing of beef products to check if they contain horse DNA.
Tests in both Norway and Austria meanwhile found horsemeat in ready-to-eat "beef" meals.
NorgesGruppen, Norway's largest retailer, said horsemeat was found in frozen lasagne dishes made by Comigel and sold in its stores. Austria's food safety agency said horsemeat was found in beef tortelloni sold in Lidl supermarkets.
Before Norway and Austria, falsely-labelled meat was found in Britain, France, Germany, and Switzerland.
Danish food safety authorities said Friday they were probing whether a slaughterhouse may have mixed horsemeat into meat marked as beef that was supplied to pizza makers.
The Dutch government's food and consumer watchdog has also searched and carried out tests for horsemeat at around 100 businesses and has stopped one company in the city of Breda from trading in meat products.
On Thursday, police in Britain arrested three men suspected of passing horse off as beef.
In a sign of the damage the scandal has done to consumer confidence, 11 major food retailers and suppliers issued a public letter in Britain on Friday saying they shared people's "anger and outrage" and were "working around the clock" to identify what has gone wrong.
Evidence of horsemeat has until now been confined to frozen products, but Asda supermarket in Britain said Thursday it had pulled a fresh beef bolognese sauce from the shelves after tests revealed it contained horse DNA.
Concerns about horsemeat first emerged in mid-January when Irish authorities found traces of horse in beefburgers made by firms in Ireland and Britain and sold in supermarket chains including Tesco and Aldi.
The scandal spiralled last week when Comigel alerted Findus to the presence of horsemeat in the meals it had made for the food giant and which were on sale in Britain.