Bernd Thissen / AFP - Getty Images

A laboratory assistant prepares a sample of lasagna for a DNA test at a veterinary research facility in Germany Thursay.

LONDON -- When officials in Ireland made a routine check on a few hamburgers, what they found made them nervous: One burger was actually nearly one-third horse.

It was a discovery that has sent shock waves reverberating across Europe.

Since the disturbing DNA test results were disclosed last month, horse meat has been found masquerading as beef in countries including the U.K., France, Germany, Sweden and Norway. 

A small amount of horse meat was also found by British officials to contain a banned drug that, in high enough doses, could be fatal, although U.K. Chief Medical Officer Sally Davies has stressed there is a "very low risk indeed" that eating contaminated meat would be harmful.

As supermarket shelves were cleared, meat suppliers in Ireland, the U.K., France, Cyprus, the Netherlands, Romania and elsewhere have come under scrutiny.

Jean-Philippe Arles / Reuters

A dump truck is filled up with blocks of meat at French meat processor Spanghero's factory in Castelnaudary near Toulouse, France, Friday.

Some in Western Europe have pointed the finger particularly at Romania, where a ban on horses in cities and the tough economic climate have been cited as reasons for a rise in exports of horse meat. The Romanians have insisted the meat was properly labeled as horse when it left the country, Reuters reported. 

According to French investigators, one French firm alone made a profit of $733,800 over six months by selling cheaper horse meat as beef in a supply chain involving 28 companies in 13 countries, Reuters reported. The company, Spanghero, protested its innocence Friday.

Intelligence agency Europol -- normally tasked with combating the trafficking of guns, drugs and humans -- was brought in to investigate what one British lawmaker has described as an “international criminal conspiracy.” Three arrests -- the first over the scandal -- were made in the U.K. on Thursday. 

Expert: Watch what you eat
Some officials believe only the “tip of the iceberg” has been revealed, and on Friday the European Union endorsed a major DNA-testing program to establish just how much unlabeled horse meat is being sold as beef or other foods.

For ManMohan Sodhi, a professor specializing in supply chains at London’s City University, the news has been a revelation.

“If you had talked to me a month ago, I would have said: ‘No, it would never happen; I completely believe in the [food supply] system,’” he said.

Now his message is “Watch out for what you eat.”

Sodhi compared the current situation to the first signs of the gross mismanagement of subprime mortgages that led to the banking crisis. “People began to uncover risks and suddenly there were too many problems,” he said.

He said large supermarkets like to deal with large suppliers who are in turn supplied by other firms and so on down to farmers and other actual food producers. At any point in the chain, someone could decide to cut costs by replacing a high-cost food with a cheap substitute.

Sodhi explained it was not in the interest of supermarkets to check their suppliers. This, he said, would be an added expense and would also make them legally liable if something went wrong.

Taking goods on trust meant they instead had “plausible deniability,” he said. “Then if something bad happens, all I do is put out an advertisement and say, ‘We really care about our customers, we’re doing everything we can … too bad somebody did something horrible.”

In a video message, Tim Smith, group technical director of supermarket giant Tesco, spoke of the firm's "unreserved apology" over the discovery of horse DNA in its frozen hamburgers and said it had dropped a supplier in Ireland.

But he also stressed the company was taking steps to ensure this never happened again.

Smith said Tesco planned to "launch a new program of activity which will test on a DNA fingerprinting basis all the meat and meat products that we source from our suppliers ... adding another layer of surveillance to help protect our customers."

On Thursday, a Tesco spokesman was unable to clarify exactly how extensive the DNA tests would be.

'Cynically and systematically duped'
Sodhi’s opinion that things could be far worse than they currently appear might be dismissed by some.

But a committee of British lawmakers that investigated the situation published a report Thursday that concluded the discoveries so far were “likely to be the tip of the iceberg” amid “suggestion of fraud on a massive scale.”

The committee concluded that it appeared consumers had been “cynically and systematically duped in pursuit of profit by elements within the food industry.”

“This scandal has also raised broader food policy questions about cheap food production, transparency, consumer confidence and pressures within the supply chain,” it added.

There are suggestions that traditional butcher’s stores have benefited from the furor.

Toby Melville / Reuters

Danny Lidgate hangs meat in the cold store area of Lidgates butchers in London Wednesday, as traditional butchers report a surge in demand from consumers.

Roger Kelsey, of the National Federation of Meat & Food Traders, estimated his members had seen an increase of up to 50 percent in demand for sausages, ground beef and burgers, according to the BBC. The British Retail Consortium, which represents supermarkets, has insisted their sales have not suffered.

Family-run store Aubrey Allen, of Leamington Spa, was named the U.K.’s Butcher’s Shop of the Year 2012 and was recently given a royal warrant to supply meat, poultry and game to Britain’s Queen Elizabeth II.

Russell Allen, who was born into the business, said supermarkets would “push and squeeze” and “bully their suppliers” to cut costs.

But he also said ordinary people shared some of the blame for the horse meat scandal by providing the demand for very cheap food.

“If you are buying five burgers for a pound ($1.55), I kind of think you get what you deserve," he said. "It suggests you don’t care, so why would you suddenly care?”

Allen said he thought people should eat better quality meat and have it less often.

He lamented the loss of a culture of cooking. Now, he said, people don't know what to do with cheaper cuts of meat and view him as strange for having homemade soup for lunch.

“Generally people say, ‘I don’t have time to cook’ and I say, ‘Well, you’ve got time to watch people cooking [on television],’” he said.

Allen said butcher’s shops were making something of a comeback after many were put out of business by supermarkets in the 1970s and 1980s.

But he admitted mass-produced food was probably here to stay. “I think it’s possibly a necessary evil on some levels. Not everyone can afford to, not everyone has the luxury of eating quality products all the time,” he said.

'Going on for years'
Frenchman Michel Roux Jr., whose restaurant Le Gavroche is one of Britain’s best, also criticized supermarkets for putting pressure on their suppliers and suggested the horse meat scandal was not a recent occurrence.

“I’m sure that it’s been going on for years, absolutely years,” he said. “It’s being done on a nod and a wink.”

Roux said he remembered as a child eating roast horse and horse burgers. And he suggested a legitimate market for horse meat might be a positive step.

Related: Horse slaughtering legal in US, but public won't bite

“Horse meat is a good meat … maybe in Britain we should embrace it, we should be eating more,” Roux said.

He said the flavor was “not too dissimilar to beef, slightly sweeter and richer,” admitting it wasn’t his favorite.

However, asked if he would put horse meat on his menu, he replied, “Not as yet.”

In Ireland, the officials who uncovered that first horse meat burger and several others with trace amounts can scarcely believe what has transpired since they went public on Jan. 15. 

Ray Ellard, director of The Food Safety Authority of Ireland, said they had been “not expecting to find too much” when they carried out a small survey of beef products.

“We were kind of … I wouldn’t say taken aback, but that’s kind of the truth,” Ellard said. “We were wondering, ‘What’s going on here?’ and wanted to be absolutely sure of the science of what we were doing.”

“We set out to do something fairly simple. We didn’t know it was going to end up where it is,” Ellard added. “It’s been painful for a lot of the food industry, some people have had reputational damage.”

“We’re glad in one way. Systems will all improve and the potential for defrauding people will be a lot less. We’re glad that that’s happened, but we had a nervous few days, I can tell you.”

Reuters contributed to this report.

Related:

European horse meat scandal spreads amid fears harmful drug entered human food chain

'Criminal conspiracy' blamed for European horse-in-burger scandal

Hamburgers pulled from UK supermarket shelves after tests reveal horsemeat

An investigation has identified a French meat-processing firm as a likely culprit in the horsemeat scandal that has enraged consumers across Europe and implicated traders and abattoirs from Cyprus to Romania.

Separately, British police investigating alleged mislabeling of beef products arrested three people on Thursday at facilities in Wales and Yorkshire that had handled horsemeat and were raided by police earlier, British media reported.

No further details on the British arrests were immediately available.

The French probe into how horsemeat found its way into ready meals sold across Europe found that the Spanghero firm labelled meat as beef when it knew what it was processing may have been horse, the government said on Thursday.

Spanghero, based in the town of Castelnaudary near Toulouse in southwest France, could have its operating license revoked and will face legal action if the suspicions are confirmed, France's consumer affairs and farm ministers told a news conference.

"It would seem that the first agent in this chain to label the meat 'beef' was indeed Spanghero," Consumer Affairs Minister Benoit Hamon said. "This was either a very big mistake or a deception for profit."

There was no indication that a Romanian firm supplying meat to Spanghero had mislabeled what was in fact horsemeat, he said, arguing that Spanghero could not have failed to notice the meat it was importing was much cheaper than beef.

"The investigation shows Spanghero knew the meat labelled as beef could be horse. There was a strong suspicion," he said.

Spanghero denied the accusations and said it firmly believed what it was selling was beef. "There is an inquiry under way which will determine whether there was negligence or not," a spokeswoman said.

The privately-owned company, founded by two brothers, sons of 1970s French rugby star Walter Spanghero, produces thousands of tons of processed meat, sold in nondescript blocks, and jars of regional dishes like cassoulet from its premises in Castelnaudary.

Horsemeat profits
The scandal, which has triggered recalls of ready meals and shattered confidence in Europe's vast and complex food industry, erupted last month when tests carried out in Ireland revealed that meat in some "beef" products was up to 100 percent horsemeat.

The British government and the European Union have called for a high-level meeting to investigate, and the issue will be on the agenda of a Feb. 25 farm ministers meeting.

The European Commission has proposed increased DNA-testing of meat products to try to establish the scale of a scandal that has exposed just how many countries a portion of mince may have traveled through before ending up in a frozen lasagna.

EU legislation states that horsemeat can be sold in meat products on the condition it is declared on the label. Member states are responsible for proper enforcement of the rules.

Hamon said the French investigation found that Spanghero had generated a profit of $733,800 over six months by selling cheap horsemeat as beef in a supply chain that reached through 28 companies in 13 countries.

He also wagged his finger at another French firm, Comigel, which used processed meat from Spanghero to make frozen "beef" ready meals, saying it should have noticed when it thawed the meat blocks that they did not look and smell like beef.

Comigel said in a statement it paid market prices for what it thought was beef. It said it had alerted the authorities as soon as it became aware of a problem and had filed a legal complaint as a victim of fraud.

It also said its frozen meat had not been thawed for inspection before entering its factory for cooking, so its staff would not have noticed anything unusual in its appearance or smell.

As regulators across Europe raced to test food products, Britain's Food Standards Agency said six horses slaughtered in Britain that tested positive for the drug phenylbutazone were exported to France and may have entered the human food chain.

Phenylbutazone, known as bute, is an anti-inflammatory painkiller for sporting horses which is banned for animals intended for human consumption as it is potentially harmful.

Asda, one of Britain's biggest supermarkets, said it was recalling its beef bolognese sauce after a preliminary test result suggested the presence of horse DNA in the product.

Related:

European horsemeat scandal spreads amid fears harmful drug entered human food chain