It is perhaps Italy's best-known export, but a number of Italy's best-known olive oil producers are being investigated for fraud.
Italy's anti-fraud police squad in Turin is examining whether seven well-known olive oil brands – Carapelli, Bertolli, Santa Sabina, Coricelli, Sasso, Primadonna and Antica Badia – have been selling lesser-quality virgin olive oil as "extra virgin" olive oil.
According to allegations in Italian press reports, samples taken from those brands found that they did not meet EU labelling rules for extra virgin olive oil. The EU has quality criteria that extra-virgin oil has to meet, such as its degree of acidity.
On its website, Pietro Coricelli rejected the allegations, arguing the test was flawed and unreliable. It said its oil had been carefully analyzed by both its own analysts and outside laboratories.
CNBC was unable to contact Deolio, a Spanish company which owns Bertolli, Carapelli and Sasso, for comment. Eurospin, an Italian supermarket which sells the Antica Badia range, declined to comment. The Italian newspaper La Repubblica reported that the companies involved all denied the allegations, however.
Supermarket Lidl, which sells the Primadonna brand, told CNBC in a statement that the allegations do not affect British consumers.
"Lidl is aware of this issue and is taking it very seriously. The background to this is an Italian test report on flaws found in extra virgin olive oil in Italy. The supplier for the 'extra virgin olive oil' products depicted in the test report does not, however, deliver product to Lidl U.K. Since Lidl U.K. sources its olive oil from other suppliers, it was not affected by these test results."
Extra virgin is the best quality olive oil as it comes from the first press of olives. Virgin olive oil is of a lesser quality but is above plain olive oil. Extra virgin olive oil can cost between 30 – 40 percent more than its lower quality cousin, according to Italian magazine, Il Test, which first discovered the alleged fraud.
In June 2015, Il Test magazine analyzed 20 bottles of extra-virgin olive oil found in Italian supermarkets and found that 9 oils did not come up to European extra virgin standards due to various defects.
Extra virgin oil has a distinct taste, color and smell that differentiate it from its cheaper counterparts but many consumers are unaware of what to look out for. Making matters harder, some producers use chemicals to cover up bad quality oils. The Italian press have called the scandal the latest to damage the "Made in Italy" brand. It is also the latest blight in what has been called an "annus horribilis" for the olive oil sector with bad weather and the olive fruit fly plaguing harvests.
Italian Agriculture Minister Maurizio Martina said in a statement that he was following the investigation in Turin and that it was essential to protect the olive oil industry as a "strategic sector" of the Italian economy. Martina said his ministry had conducted 6,000 checks on the sector last year, with seizures equating to 10 million euros.
"It is important to clarify what's going on for consumers and thousands of honest companies engaged in olive oil production," he said, according to a statement in Corriere della Sera.
- By CNBC's Holly Ellyatt, follow her on Twitter @HollyEllyatt. Follow us on Twitter: @CNBCWorld