Added DNA could be used to authenticate premium olive oil
By Ben Coxworth
April 25, 2014
When most people think of counterfeit goods, they probably picture things like handbags or watches. In fact, there's also a huge market for knock-off high-end food products, such as extra-virgin olive oil. Scientists from Switzerland's ETH Zurich research group, however, have come up with a possible method of thwarting the makers of that bogus oil – just add synthetic DNA particles to the real thing. And yes, consumers would proceed to swallow those particles.
Because DNA can be damaged by exposure to chemicals, light, and fluctuations in temperature when outside of a living organism, the particles are first encased in a protective silica coating. Iron oxide nanoparticles are also added, which come into the picture later.
The DNA particles can then be added to olive oil, with quite a small amount of them being sufficient for the task at hand – according to ETH, "Just a few grams of the new substance are enough to tag the entire olive oil production of Italy."
When stores subsequently wanted to verify the authenticity of tagged oil, they could use a magnet to retrieve some of the DNA particles from a sample of the liquid. This is where the attached iron oxide comes in, as it's drawn to magnets.
The DNA is then freed from its silica shell using a fluoride-based solution, and analyzed via an inexpensive process known as polymerase chain reaction (PCR). If the code of the sampled DNA matched the code that was recorded when the DNA was added by the manufacturer, then the oil would be the genuine article.
Although it would be extremely difficult for counterfeiters to create DNA with that same code, they might be tempted to instead just add a bit of the authentic tagged oil to their own product, thereby mixing in some of its DNA. That wouldn't work, either, however, as it's also possible to measure the concentration of DNA particles in a sample – again, that amount would have to match the value that was recorded by the original manufacturer.
The particles reportedly don't alter the appearance or taste of the oil, and are said to be harmless to ingest. Silica and iron oxide are essentially sand and rust, and are already present in some commonly-consumed foods. As for DNA, we eat it every time we eat plant or animal products. That said, lead scientist Robert Grass thinks that the technology might go over better with consumers if the synthetic DNA were replaced with natural DNA, such as that of fruits or vegetables.
Application of the DNA particles would reportedly cost about 0.02 cents per liter of oil. The tagging system could also be used on a wide variety of other liquids, and has already been successfully tested on Bergamot essential oil, which is used in perfumes. Scientists at Portugal's University of Aveiro are working on a similar system, in which DNA "barcodes" can be added to both liquids and dry goods.
A paper on the ETH research was recently published in the journal ACS Nano.
Source: ETH Zurich