We are certain it goes on at all levels

We are certain it goes on at all levels."The French Black truffle is the mushroom fruiting body of a particular fungus, the Tuber melanosporum, that grows a few centimetres underground in symbiotic association with the roots of oak and hazelnut trees. The edible portion forms in the autumn and harvesting takes place in winter once the truffle has matured.Its uniquely pungent odour, rich, delicate flesh, its rarity and the traditions associated with its discovery have for centuries filled the hearts of the French with gastronomic pride. France is the only place in the world where the Tuber melanosporum will grow naturally.The ancient Greeks and Romans attributed therapeutic and aphrodisiac powers to the French Black truffle, beliefs still in vogue in the last century. The celebrated 18th-century French gourmet, Brillat Savaurin, in his La Psychologie de Gout ("The Psychology of Taste"), claimed that truffles "aroused erotic and gastronomic memories among the skirted sex, and memories gastronomic and erotic among the bearded sex". Alexandre Dumas, author of The Three Musketeers, described them as the "gastronomic holy of holies".The mystery of the truffle begins with its discovery Generally, there are three accepted ways to hunt it. The first technique involves a female pig, the classic and most foolproof truffle detector known to man.

Recent German research has shown that the truffle contains a steroid produced by male pigs during pre-mating behaviour. This steroid acts as a pheromone, hence the attraction for the female pig.The only snag is that it is difficult to control a pig on the brink of ecstasy. It is not surprising, therefore, that dogs have become much more popular in recent years Unlike pigs, dogs do not dig instinctively for truffles. They are trained with a slice of dry sausage dipped in truffle sauce, so the dog can associate the scent of the fungus with his favourite snack.The final method involves poking around the base of hazelnut and oak trees with a stick. If an insect rises from the roots, you may have disturbed a member of the truffle fly family, which lay their eggs on the esteemed fungus. Many truffists have adopted this technique because walking around with a stick is less obvious than walking around with a pig, and secrecy can more easily be preserved.Around the turn of the century there was a lively trade in English truffles (Tuber aestivum) around the Winterslow area of Wiltshire, where they were sniffed out from the roots of beech trees by Spanish poodles.

But the trade died out with the retirement of the last English truffle hunter, Alfred Collins, in 1930.Legend has it that Alfred could smell truffles and feel them underfoot On his best days, he collected as many as 25lbs. In 1920, he put his price up to 2s 6d per pound, but by the time he retired he could get 5s 6d per pound (only 2712p in modern money but quite a tidy sum in 1930) Alfred, however, died a poor man. His father once found a truffle weighing more than 2lbs, which he sent to Queen Victoria, who replied saying she would send him her portrait. Several weeks later a silver coin arrived with the image of the monarch on it.Toward the end of the last century, France produced up to 1,000 tons of French Black truffles. Since then, output has fallen dramatically, mainly because of the abandonment of land cultivation, deforestation and possibly acid rain.

In the 1960s, when the yearly output was down to four tonnes, the French government undertook an extensive research programme in an effort to save the industry. By the 1970s, a technique to inoculate oak and hazelnut trees was developed and achieved some limited success. A number of companies using this technology under licence have produced and marketed several hundred thousand trees, but as much as 70 per cent of truffles still come from native oak and hazelnut forests.What makes a truffle grow is one of nature's enduring mysteries. Current scientific thinking leans towards a good spring and autumn rain, soil temperature, pH levels, calcium content and latitudinal meridian."If the market is left unfettered by cheap and inferior imitations, I believe the future is bright for the truffle industry," said Pierre Sourzat. "But all our efforts will be in vain if the Chinese truffle continues to be mixed and confused with the beautiful and delicious black diamond."The future of the truffle is not all doom and gloom. With aid of French technology, various other countries - including Italy, Spain, the United States, Israel, New Zealand and Australia - have been attempting to grow the prized Tuber melanosporum.