ROME — Think about the last time you had really, really good extra-virgin olive oil. The kind of pungent oil that tickles the back of the throat and drips like green liquid gold from your crusty bread or lettuce leaves. You probably paid a small fortune for it. Sadly, if it was from Italy, it might not have been as virgin as you think.

This week, Italian prosecutors in Turin opened a criminal investigation into seven of the country’s top olive oil export companies: Carapelli, Bertolli, Santa Sabina, Coricelli, Sasso, Primadonna, and Antica Badia for allegedly cutting the good stuff with less precious oil.

After an Italian food blog broke the news that expensive oil being passed off as extra-virgin might be stained last May, Italian agriculture and customs started doing their own tests and found that in nine out of every 20 bottles these producers sold in country or exported out were tainted. Italy is the second largest olive oil producer in the world after Spain. But Italy is also the world’s largest importer of olive oils from Tunisia, Morocco, Greece, and Spain. They also import canola and soybean oil from abroad. Many producers happily admit to using the imported oil as a base for their lesser-quality and industrial oils, stating exactly where the oil originated in often miniscule print on the labels. And there is nothing illegal at all about it.

The problem—read fraud—comes from the fact that the companies under investigation are accused of importing canola and even soybean oil to mix into their expensive oil sold as extra-virgin. By law, extra-virgin has an acidity of no more than 0.8 grams per 100 grams of oil, and it must be made from the first press of the olives, which, if up to standards, commands a price tag that is often up to 35 percent more than other oil. If not, it should sell for much less—and say so on the label.

All of the Italian olive companies under criminal investigation deny any wrong-doing, citing faulty testing. Many have launched counterattacks, accusing authorities of fraud, which, in Italy, is not always a long shot. What’s troubling is that farmers and olive oil producers at the center of the investigation are being accused of cooperating with the so-called agro-mafia which is a catchall label often used in Italy for fraudulent behavior and corruption in the agriculture sector, which may or may not have anything to do with the country’s established organized crime syndicates. But it often does, and many organized crime syndicates’ tentacles reach into every facet of Italian life and livelihood.

“It is often difficult to understand the economic impact of agro-mafia but those who produce olive oil are increasingly in the crosshairs of professional counterfeiters,” says Domenico Pautasso, director of Italy’s national agriculture association Coldiretti. “The turnover of the agro-mafia exceeds €15.5 billion, and the entire system of false ‘made in Italy’ products exceeds €60 billion a year.”

In fact, the Italian Confederation of Agriculture estimates that there are 240 agro-mafia offenses every single day in the agriculture sector. That breaks down to eight crimes every hour, according to a report called “Agromafia” published last year. The report states that more than 350,000 farmers and producers are involved in the widespread fraud, that runs the gamut from faulty pasta to counterfeit cheeses and hams. Some of the farmers and producers are victims who sell their authentic products to producers who compromise their integrity for higher profits; others are knee-deep in the quagmire of corruption.

The Confederation of Agriculture estimates that of the illicit industry’s profits, some €4.5 billion is generated from blatant theft and robbery of authentic products from fields and warehouses. An estimated €3.5 billion of the dirty revenue comes from racketeering, and around €3 billion is generated from counterfeiting of the “made in Italy” brands.

Italian anti-mafia and anti-corruption authorities work tirelessly to try to stop the widespread practice that has been identified in every single province in Italy in one sector or another. In 2014, they confiscated more than 12,000 properties, including farmland and production facilities. “The presence of organized crime affects the entire system, from production to distribution,” says Pino Cornacchia, Head of the Confederation of Agriculture’s Campania Economic Development Department. “It is also a massive deterrent to all young people otherwise keen to invest in the primary sector.”

It is not the first time Italian olive oil has been tainted by scandal. In 2011, New York Times contributor Tom Mueller laid out the scandal in his book, Extra Virginity: The Sublime and Scandalous World of Olive Oil in which he reported that more than 50 percent of all olive oil imported into the United States is adulterated with lesser oils. “In the past, the technology that had been used had been used really by the Romans,” Mueller writes. “You grounded the olives with stone mills and you crushed them with presses.”

Everything has apparently been downhill since then.

So what is a lover of olive oil to do? “For those who buy it is important to pay attention to the label,” Alberto Martorelli of Coldiretti told The Daily Beast. “Make sure you only buy oil made with 100 percent olive oil produced and bottled in Italy if you want authenticity. And make sure it passes the smell test. It should smell and taste like raw olives.”

Sadly, though, it seems even that is no guarantee.