When is a black truffle not a €1,000-a-kilo rare French fungus? When it fails the smell test.
In their battle to see off competition from pale and cheap Chinese imitations, French trufficulteurs (truffle cultivators, as they like to be known), have enlisted the help of scientists.
And as the truffle season gets into full swing, French sellers are seeking to identify the smells that make the highly prized tuber melanosporum or black truffle – found in south-west France and known as the "black diamond" – distinct from its distant and considerably cheaper cousin, the tuber indicum from Sichuan and the Himalayan foothills.
A team of experts from the National Institute of Agronomic Research (INRA) at Avignon is attempting to establish the "olfactory qualities" of the European truffle.
"From the key components of the smell, we should also be able to determine the soil from where the truffle comes," Christian Ginies, head of the INRA research team told Reuters.
"In any case we will be able to tell the difference between a truffle from Périgord and a truffle from China. Knowing the characteristics of a product better can help with better communication about truffles, but also help to deal with fraud."
Four years ago, French scientists established the genome sequence of the black Périgord truffle, a fungus that grows with oak and hazelnut trees and is sought for its rich, musty smell and flavour.
On Friday a small army of truffle inspectors was despatched to local markets with microscopes and DNA kits to attempt to root out foreign impostors.
French truffle sellers insist the Chinese fungi, which sell at a relatively paltry €30 (£25) a kilo, are vastly inferior to the melanosporum but are easily confused with – and often passed off as – the European truffle.
Unscrupulous sellers have been accused of slipping Chinese truffles into baskets of black truffles to soak up the pungent smell, or serving them sprayed with truffle scent.
Jean-François Tourrette, president of the regional federation of trufficulteurs in Provence, said analysing the smell of the truffles would enable them to be identified "in the same way as a wine". "We are trying to obtain a labelling system to give the European truffle an identity to combat the massive imports of Chinese truffles," Tourrette said. "It's a perfect tool to avoid customers being cheated; so that they're not paying a lot of money for something that tastes like cardboard."
It used to be said that French truffles – used in haute cuisine and synonymous with luxury – were hunted by pigs and served to humans, while Chinese truffles were found by humans and fed to pigs.
Since 1989, when Chinese farmers discovered they were wasting a small fortune on their domestic animals, they have been saving the fungi for export.
Over the past century, tree clearance has led to France's production plummeting from 1,600 tons a year to about 40 tons. The Chinese produce about 300 tons, of which 15 tons are exported to France.
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