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Flanders fights fish fraud with DNA tool

A dish of Mediterranean cod. Or is it? © Avid Vines

How easy is it to tell a haddock from a halibut?*

There are so many fish in the sea, and for most people it’s difficult to tell one sort from another.

That’s a fact that’s often exploited by unscrupulous traders, as well as restaurant owners. The trick involves taking a cheaper species of fish and selling it as the more expensive sole or cod.

By the time the fish has been sold and worked on in the restaurant kitchen or turned into a ready meal for the supermarket, even the trained eye might have trouble identifying the fish correctly.

But now the Flemish Institute for Agricultural, Fisheries and Food Research (Ilvo) has developed a tool to determine in seconds whether a piece of fish is what it claims to be.

The technique consists of creating a barcode for each of the 42 types of fish cleared for commercial sale. Those are loaded into a database.

If an inspector at any level of the trade from boat to plate has a suspicion that one fish has been substituted for another, all it requires is for a tiny sample of the fish to be sent to the Ilvo lab, where it can be compared against the database which immediately reveals the species of fish concerned.

The institute now wants to see its tool put to use at all levels.

It is not always clear exactly where fraud is being committed,” said Ilvo spokesperson Greet Riebbels. “The fake fish in the supermarket might, for example, have been exchanged during import, wholesale or processing. The study shows that fish fraud can be anywhere in the chain, so that a broad check is required.”

According to one field test, it was found that sole had been substituted by a cheaper fish in 17% of cases. When it came to cod, the figure was only 2%.

* The answer in this case is: very easy. A halibut is the largest of the flat fish, which can measure up to two metres in length; whereas a haddock is a round fish of the cod family, the largest reaching a length of 94cm.

Alan Hope
The Brussels Times