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Protecting
olive oil from counterfeiters
Protecting
olive oil from counterfeiters
Date:
April 24,
2014
Source:
ETH Zürich
Summary:
Who guarantees that expensive olive oil isn't
counterfeit or adulterated? An invisible label could perform this task. The tag
consists of tiny magnetic DNA particles encapsulated in a silica casing and
mixed with the oil. The worldwide need for anti-counterfeiting labels for food
is substantial. In December 2013 and January 2014, Interpol and Europol
confiscated more than 1,200 tonnes of counterfeit or substandard food and
beverages. The confiscated goods also included more than 131,000 litres of oil
and vinegar.
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Who guarantees that expensive olive oil isn't counterfeit or
adulterated? An invisible label, developed by ETH researchers, could perform
this task. The tag consists of tiny magnetic DNA particles encapsulated in a
silica casing and mixed with the oil.
Just a few
grams of the new substance are enough to tag the entire olive oil production of
Italy. If counterfeiting were suspected, the particles added at the place of
origin could be extracted from the oil and analyzed, enabling a definitive
identification of the producer. "The method is equivalent to a label that
cannot be removed," says Robert Grass, lecturer in the Department of
Chemistry and Applied Biosciences at ETH Zurich.
The
worldwide need for anti-counterfeiting labels for food is substantial. In a
joint operation in December 2013 and January 2014, Interpol and Europol
confiscated more than 1,200 tonnes of counterfeit or substandard food and
almost 430,000 litres of counterfeit beverages. The illegal trade is run by
organised criminal groups that generate millions in profits, say the
authorities. The confiscated goods also included more than 131,000 litres of
oil and vinegar.
A forgery-proof
label should not only be invisible but also safe, robust, cheap and easy to
detect. To fulfil these criteria ETH researchers used nanotechnology and
nature's information storehouse, DNA. A piece of artificial genetic material is
the heart of the mini-label. "With DNA, there are millions of options that
can be used as codes," says Grass. Moreover, the material has an extremely
low detection limit, so tiny amounts are sufficient for labelling purposes.
Synthetic
fossil
However, DNA
also has some disadvantages. If the material is used as an information carrier
outside a living organism, it cannot repair itself and is susceptible to light,
temperature fluctuations and chemicals. Thus, the researchers used a silica
coating to protect the DNA, creating a kind of synthetic fossil. The casing
represents a physical barrier that protects the DNA against chemical attacks
and completely isolates it from the external environment -- a situation that
mimics that of natural fossils, write the researchers in their paper, which has
been published in the journal ACS Nano. To ensure that the particles can
be fished out of the oil as quickly and simply as possible, Grass and his team
employed another trick: they magnetised the tag by attaching iron oxide
nanoparticles.
Experiments
in the lab showed that the tiny tags dispersed well in the oil and did not
result in any visual changes. They also remained stable when heated and
weathered an aging trial unscathed. The magnetic iron oxide, meanwhile, made it
easy to extract the particles from the oil. The DNA was recovered using a
fluoride-based solution and analysed by PCR, a standard method that can be
carried out today by any medical lab at minimal expense. "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," write the researchers. The
method also made it possible to detect adulteration: if the concentration of
nanoparticles does not match the original value, other oil -- presumably
substandard -- must have been added. The cost of label manufacture should be
approximately 0.02 cents per litre.
Labels for
petrol and Bergamot essential oil
Petrol could
also be tagged using this method and the technology could be used in the
cosmetics industry as well. In trials the researchers also successfully tagged
expensive Bergamot essential oil, which is used as a raw material in perfumes.
Nevertheless, Grass sees the greatest potential for the use of invisible labels
in the food industry. But will consumers buy expensive 'extra-virgin' olive oil
when synthetic DNA nanoparticles are floating around in it? "These are
things that we already ingest today," says Grass. Silica particles are
present in ketchup and orange juice, among other products, and iron oxide is
permitted as a food additive E172.
To promote
acceptance, natural genetic material could be used in place of synthetic DNA;
for instance, from exotic tomatoes or pineapples, of which there are a great
variety -- but also from any other fruit or vegetable that is a part of our
diet. Of course, the new technology must yield benefits that far outweigh any
risks, says Grass. He concedes that as the inventor of the method, he might not
be entirely impartial. "But I need to know where food comes from and how
pure it is." In the case of adulterated goods, there is no way of knowing
what's inside. "So I prefer to know which particles have been
intentionally added."
Story
Source:
The above
story is based on materials provided by ETH Zürich. The original article was written by
Barbara Vonarburg. Note: Materials may be edited for content and length.
Journal
Reference:
- Michela Puddu, Daniela Paunescu, Wendelin J. Stark, Robert N. Grass. Magnetically Recoverable, Thermostable, Hydrophobic DNA/Silica Encapsulates and Their Application as Invisible Oil Tags. ACS Nano, 2014; 8 (3): 2677 DOI: 10.1021/nn4063853
Cite This
Page:
ETH Zürich. "Protecting olive
oil from counterfeiters." ScienceDaily. ScienceDaily, 24 April 2014.
<www.sciencedaily.com/releases/2014/04/140424102309.htm>.