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Nanotech Can Ensure You're Only Getting the Purest of Olive Oils

Consuming iron oxide and artificial DNA sounds a lot worse than it is.
Image: Ryan O'Connell/Flickr

Fake olive oil is—believe it or not—a big problem, but it's now getting a tiny solution. In a paper in ACS Nano, Swiss researchers demonstrated a way to “tag” oil with a few grams of DNA wrapped in a tiny magnetic silica capsule while the oil is being bottled. That way, if someone doubts the extra virginity of the olive oil, they can extract and analyze the marker—mystery solved, tortellini saved.

Between December 2013 and January 2014, Interpol and Europol confiscated more than 1,200 tonnes of counterfeit or substandard food, and 430,000 liters of counterfeit beverages. This included more than 131,000 liters of oil and vinegar. An estimated 70 percentof the extra virgin olive oil imported to the US has been adulterated, meaning that it's cut with cheaper oils, like vegetable oil disguised with chlorophyl and beta carotene to look like the good stuff. But counterfeit olive oil is actually really difficult to detect—lab tests were so easy to fool, that officers in a special branch of the Italian Carabineri were trained to rely on the smell test instead.

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So there's a potential market for a permanent olive oil marker, and that's basically what this is, according to the study's co-author Robert Grass. “The method is equivalent to a label that cannot be removed,” he said in a statement. And to make something small and clear, the researchers modeled their label after DNA. "With DNA, there are millions of options that can be used as codes," Grass explained. Then, to keep the DNA in tact, and also make it easy to extract with a magnet, they coated it in silica and attached some iron oxide nanoparticles. That way it would be easy for anyone with a basic medical lab to verify their oil.

Image: ETH Zurich

Okay, I realize that sounds like something you don't want floating in your fancy-pants olive oil. It's unlikely that anyone has ever said, “Gosh, this rigatoni could really use more silica and iron oxide,” but you're unwittingly chowing down on silica in ketchup and orange juice—and iron oxide as a food additive—already, Grass said reassuringly. Plus it would only take just a little tiny bit. “Unbelievably small quantities of particles down to a millionth of a gram per liter and a tiny volume of a thousandth of a liter were enough to carry out the authenticity tests for the oil products,” the researchers wrote.

The procedure was also tested for the barcoding of gasoline and bergamot oil, a key ingredient in perfume, to verify their authenticity, which is good, because there's always a possibility that pure olive oil isn't the most important thing the in the world. According to The Guardian's Alex Renton, when olive oil importers and foodies do blindfolded taste testing, they don't actually prefer real olive oil:

“The [blind taste test] results were so embarrassing and confusing the piece was never published. The importer went into a fugue after he was informed that he'd pronounced his own premium product "disgusting"; the deli owner chose a bottle of highly dubious "Italian extra virgin" as his favourite (it had cost £1.99 at the discount store TK Maxx); and both the foodies gave a thumbs-up to Unilever's much-derided Bertolli brand.”

So, you know, if you're not worried about collapsing the international olive oil trade, maybe just buy the cheap stuff and embrace the mystery. Or insist that your rigatoni come with some DNA wrapped in silica, with just a hint of iron oxide.