A horse butchery is pictured in Munich, Germany. The horsemeat scandal spreads across Europe after horse meat falsely labeled as beef was discovered in lasagnas and burgers in Britain, Ireland, Sweden and France. (STEPHAN JANSEN/EPA)

According to folklore, Europeans have always treated their food with reverence, eating Grandma’s slow-cooked stews concocted with farm-fresh ingredients while Americans wolfed down the genetically modified, chemically preserved junk that is symbolized by burgers and fries.

Over the past two weeks, however, Europeans have watched an unfolding meat-fraud scandal expose a multinational network of traders, factory owners and marketers for whom food is a stateless commodity that can be hashed up, frozen and shipped around the continent to be profitably passed off as genuine cuisine to Swedes, Italians, Czechs or French alike.

So much for Grandma.

The scandal erupted Feb. 7 when Britain’s Food Standards Agency discovered horsemeat mixed into frozen lasagna labeled as 100 percent beef. Horse-loving Britons, who would never think of eating Black Beauty, were shocked, all the more so in that the lasagna came from across the English Channel.

“It’s a straight fraud,” said Britain’s environment minister, Owen Paterson, giving voice to the outrage of English consumers. “If a product says it’s beef and you’re actually buying horse, that is a fraud.”

But that was just the beginning. By Tuesday, the shock had spread across Europe, even to countries such as France, where people routinely eat horsemeat. Prepared dishes labeled as beef, it turned out, have been commonly laced with cheaper horsemeat and sold at frozen-food counters across the continent. There is no telling how long the cheating has been going on or how much is undiscovered.

In reaction, frozen dishes such as shepherd’s pie, pizza and meatballs have been withdrawn from hundreds of multinational-chain supermarkets in at least 16 countries. A dozen national investigations have been launched. The European Union has vowed to require meat merchants to conduct costly DNA testing. French President Francois Hollande said that all meat products sold in France must bear a label of origin, just like wine.

“The entire sector has fallen victim to a fraud without precedent,” said Jean-Rene Buisson, president of the French National Association of Food Industries.

For many Europeans, the issue was less disgust at eating horsemeat than the dishonesty involved in false labeling. But Fabrice Nicolino, a journalist who writes about the food industry and the environment, warned that testing could well turn up unhealthy residue from anti-inflammatory drugs that are often administered to horses.

“Nobody really knows what industrial meat contains,” he wrote Monday in Le Monde.

Perhaps even more unsettling was the spotlight suddenly directed at a modern agro-industry that, with few people noticing, has left picturesque farmers’ markets far behind and, instead, trades in bulk food across borders much as other industries trade in diamonds or oil.

Giving the lie to images of rosy-cheeked peasants and busy family kitchens, more than 90 percent of European households at least occasionally buy ready-made frozen dishes, according to industry research. Britain and Germany lead European consumption of such dishes, but France is not far behind in third place.

For some activists, the new eating habits have long been a concern. Jose Bove, a sheep farmer from southwestern France who is now a member of the European Parliament, rose to fame in 1999 by trashing a McDonald’s outlet in the farming town of Millau, France, to dramatize his opposition to industrial food.

“The new way of eating prepared dishes from big supermarkets makes it easy to disguise this kind of business,” he told reporters as the horsemeat scandal was unraveling.

French authorities, tracking the falsely labeled lasagna dishes, zeroed in on a small meat-processing company in Castelnaudry, near Carcassonne, in southwestern France. The company, Spanghero, bought horsemeat in Romania and sold it as beef, according to Benoit Hamon, a deputy finance minister in charge of consumer protection.

The deal was particularly profitable at this time, according to news reports from Bucharest, because Romanian farmers were selling their horses to slaughterhouses in large numbers after a new law banning horse-drawn vehicles on country roads.

After being transported with accurate labeling from a Romanian slaughterhouse, the frozen horsemeat was relabeled as beef and sold to the highest bidder, according to the ministry’s investigation. Without changing locale, the meat went through the hands of at least two traders, one in Cyprus and another in the Netherlands, who had previously been fined for fraudulent meat labeling, the ministry said.

The traders eventually sold and shipped the meat to Comigel, a large-scale processing firm with a plant in Metz, in eastern France, and administrative offices in Luxembourg, a tiny duchy sandwiched between France and Germany that often serves as an address for tax-dodging businesses, the investigation showed.

Without suspecting that the meat came from horses — and without checking — Comigel diced it up and manufactured thousands of frozen dishes such as pizza and pot pies, according to the inquiry. The dishes were produced under a number of brand names on contract to a variety of multinational chains across Europe, it found.

After a crisis meeting in Brussels with his E.U. counterparts, Hamon announced plans to focus increased attention on the food industry to prevent a recurrence of the labeling fraud and ensure that meat sold in French stores is marked with its place of origin.

European law requires that labels include the type of meat being sold — beef, pork, lamb — but not its origin. An E.U. official in Brussels noted to reporters that if the label is fraudulent, a new mandate to include origin “changes nothing.”

Although Spanghero’s management denied acting illegally, the company’s operating license was suspended, putting about 300 employees out of work. But the license was renewed a week later, after the workers protested that they were being scapegoated and Spanghero pledged to halt its involvement in the wholesale trade of unprocessed meat.

Subsequent discoveries of horsemeat in prepared dishes, including one in the Czech Republic that led Ikea to withdraw meatballs from its furniture stores in a dozen countries, have raised suspicions that Spanghero might not be the only source of mislabeled meat. E.U. and national authorities have stepped up testing to find out.

In the meantime, Perico Legasse, gastronomy critic for France’s Marianne magazine, treated readers this week to a recipe for lasagna — the real thing, from scratch, with fresh meat.

Anthony Faiola in London contributed to this report.