Storm in a pesto jar: Italian producers at odds with scientists over cancer scare

A bitter row has broken out in Italy over the alleged toxicity of one of the nation's favourite foods: pesto. The Genovese sauce prepared for centuries in Ligurian kitchens by grinding together fresh young basil leaves, garlic, pine nuts, parmesan cheese and olive oil contains a carcinogenic ingredient, a leading Italian scientist warns. And the tastier the pesto, the greater the danger.

A bitter row has broken out in Italy over the alleged toxicity of one of the nation's favourite foods: pesto. The Genovese sauce prepared for centuries in Ligurian kitchens by grinding together fresh young basil leaves, garlic, pine nuts, parmesan cheese and olive oil contains a carcinogenic ingredient, a leading Italian scientist warns. And the tastier the pesto, the greater the danger.

The problem ingredient is a carcinogenic agent called methyl-eugenol, which is found to be present in the leaves of young basil plants, up to 10 centimetres in height, from the best plantations in Liguria - the optimum basil for use in pesto doc (for "denomonazione origine controllata").

According to Professor Francesco Sala of the Umberto Veronesi Foundation, in a plate of spaghetti with pesto doc "there is a concentration of methyl-eugenol 600 times higher than the accepted safety limit. Which is not to say that it produces tumours, but that it increases the probability of having them". Using adult basil, Professor Sala goes on, the risk is eliminated. Why? "The methyl-eugenol protects the young plant from insects and bacteria. Then, as it grows, the molecule loses its methyl and becomes harmless." And also, the aficionados claim, far less appetising.

But with their full frontal assault on one of Italy's proudest food inventions, Professor Sala and his colleagues may have bitten off more than they can chew. The guardians of the pesto tradition were quick to condemn the new attack.

"We're on our own," ruminated Sergio and Riccardo Bertola, chefs of Genoa's Gran Gotto restaurant. "The big firms want to sell their 'pesto sauce' made with Kenyan basil and preservatives instead of sea salt. They dragged out this stuff [about pesto being carcinogenic] years ago, then they said it wasn't true ... Is it really necessary to beat up on pesto? Okay, we're not professors but we've been making pesto like this for centuries."

The region of Liguria recently won a battle over the definition of pesto, forcing Nestlé to withdraw a pesto sauce "à la Genovese" made with basil grown from German and Swiss seeds. At the same time Liguria and 13 other Italian regions two weeks ago declared themselves "GM-free zones".

This week's claims about pesto came as part of a last-minute offensive by pro-GM scientists to prevent a government ban on the growing of GM crops. The legislation, due last month, has been delayed by wrangles within the ruling centre-right coalition, but is expected to be presented to parliament next week.

The argument of the scientists is that while GM foods can be eaten with absolute confidence, given the amount of research that has been done on them, the "natural", "organic" foods vaunted by Italy's army of foodies may contain hidden hazards.

The attack on basil is not in fact new: it was in 1999 that researchers discovered by chance that the best pesto may also be the most hazardous.

The discovery was made at Genoa's Centre for Biotechnology, Professor Sala said. "The objective [of the research] was to explain why pesto doc is better than other types. The substance that was isolated, in fact, makes the difference in flavour." The original publication of the claim that Italy's best pesto might be bad for you sparked a furious controversy, after which, Professor Sala maintains, "everyone was told to shut up".

The reiteration of the charges this week came as the Umberto Veronesi Foundation published a pro-GM manifesto entitled Food Safety and GM Organisms, edited by 19 Italian scientific organisations claiming to represent 10,000 researchers. The manifesto aims to combat what Professor Veronesi, a former Italian health minister, calls "the absurd demonisation" of GM foods.

Hostility to GM foods, he said, "was initially considered an understandable caution in the face of something of little importance, but in the light of studies on populations that for years have been living on GM foods, the US above all, it has become an opposition that must be eliminated because it is dangerous for our country."

He went on: "I would like to eat GM maize all the time, I would feel safer doing so. In the USA I eat it with pleasure, while in Italy I don't have the freedom to choose what is much safer than the so-called organic variety."