What's really on your plate? DNA barcoding and food fraud

Victoria Veldhoen
3 August 2013

Above: Image © istockphoto.com/Franck-Boston

In Canada, impersonating a police officer is a criminal offence. It can result in as much as $5000 in fines, up to six months in jail, or both. But what if your favourite sushi house says they're giving you a tuna roll, but they serve you an entirely different fish dressed up to look the part? When a merchant deliberately mislabels a food product with the intention of deceiving the consumer, they're committing food fraud.

Did you know? Examples of food fraud uncovered via DNA barcoding include “sheep's milk cheese” made from cow’s milk and “venison” dog treats made from beef.

In the past, detecting food fraud was more difficult because it was hard to distinguish between ingredients with similar properties—ones that look the same, smell the same, etc. But thanks to DNA barcoding, it’s now possible to detect exactly what's on your plate. The general principle behind DNA barcoding is to assign a unique DNA tag to each individual species, much like how each item at the grocery store has its own UPC code. This DNA tag makes it possible to trace any ingredient back to a specific species.

As more and more species are added to DNA barcoding databases, detecting food fraud becomes even more effective. And due to the sheer resilience of DNA, it’s possible to trace the biological origins of food that has been frozen, fried, or chemically altered. The one exception is canned foods, which are processed at temperatures high enough to break DNA into very small fragments.

A seller mislabelling their product might think they're not hurting anyone. They make a bit of extra profit and the consumer is none the wiser. But for people who have food allergies, follow religious dietary restrictions, or simply want to get what they're paying for, food fraud is a very real concern. Mislabelling food can also be considered theft.

Did you know? Recent studies have found that seafood species like salmon, Atlantic cod, and red snapper are mislabelled between 25% and 70% percent of the time.

In 2013, Chinese merchants were found to be charging extravagant prices for “lamb” that actually turned out to be rat meat. Meanwhile, a scandal erupted in Europe, where food products claiming to contain “pork” or “beef” really contained up to 100% horsemeat. The incident caused significant concern in several European countries where eating horsemeat is considered taboo.

If they are caught, the consequences for purveyors of adulterated meat can be dire. In China, dozens were arrested for selling rat meat. In Europe, companies responsible for distributing mislabelled horsemeat have lost most of their clients. And thanks to the power of DNA barcoding, it’s getting easier to keep suppliers honest about what they're selling to their consumers.


General news and science websites

Canadians develop system to detect food fraud (CBC News) Student Sleuths Using DNA Reveal Zoo of 95 Species in NYC Homes – And New Evidence of Food Fraud (ScienceDaily) NYC Students Reveal Food Fraud with DNA Barcoding (Jeremy Hsu, Popular Science) Rats! More Food Fraud. (No Really, Rat Meat!) (John Spink, Michigan State University)

Government websites

Food fraud (Food Standards Agency UK)

Conservation group websites

What is Seafood Fraud? (OCEANA)

Press releases

Tesco Comments on Test Results (Tim J Smith, Tesco PLC) EU-Wide meat testing proposed for horse DNA (SGS)

Victoria Veldhoen

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