Fake Olive Oil Scourge Could Be History After Scientists Invent Magnetized Nano-Tag
In February, Interpol and Europol announced a major international bust. It wasn't drugs, though. It was fraudulent and substandard food, including some 34,600 gallons of oil and vinegar. Olive oil counterfeiting — the practice of spiking olive oil with lesser oils like sunflower seed oil — is such a major problem that the European Union has an olive oil task force.
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Now science has dealt, potentially, the biggest blow yet to oil fraudsters. "Invisible oil tags," invented by chemists in Zurich, are nano-scale DNA sequences encased in silica that could be added in extremely small amounts to pure olive oil at its source, leaving a tag for anyone to read further down the chain of supply. They presented the idea this week in the journal ACS Nano.
"The method is equivalent to a label that cannot be removed," says Robert Grass, a chemist at ETH Zurich, in a statement announcing the invention. He added that "with DNA, there are millions of options that can be used as codes." The nano-tags would be safe to consume, invisible, and inexpensive. The amount of oil-tag additive necessary to safeguard the entire oil product of Italy would be "just a few grams."
"Unbelievably small quantities of particles down to a millionth of a gram per litre and a tiny volume of a thousandth of a litre were enough to carry out the authenticity tests for the oil products," they wrote in the paper. With a concentration that small, it would've been difficult to wade through enough oil to find a tag. So they magnetized the particles by attaching iron oxide to them. Additionally, the DNA is encased in silica because genetic material outside of living organisms has a tendency to be damaged easily by temperature and light changes.
It's easy to see how this could be useful for other easily counterfeited liquids. In addition to olive oil, the researchers also tested their DNA barcodes on gasoline and cosmetic oil. Yet in food, the idea of eating DNA, silica, and iron oxide sounds less than appetizing. Grass acknowledges that there may be strong resistance to intentionally causing an impurity in order to ensure purity, but he says these are things that people consume anyway. He sees it as a net benefit. "I prefer to know which particles have been intentionally added," he says.
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