THE MARKET FOR EUROPEAN TRUFFLES, THE WORLD'S MOST EXPENSIVE FOOD, IS BEING DILUTED WITH CHEAP CHINESE IMPORTS - "60 MINUTES" SUNDAY

Ounce for ounce, European truffles are the world's most expensive food, and not just because they taste so good on haute cuisine. The white truffles sell for about $9,500 a pound, while the black variety goes for over a $1,000 a pound. But whichever variety you choose, they are both rare and expensive. The specially-trained dogs that are used to find them are as prized as the pricy fungus itself. But there's trouble in truffle land, as Lesley Stahl finds out in Italy and France. Harvests are down and a black market has emerged that has allowed an influx of inferior and cheap Chinese truffles that are diluting this lucrative market. Stahl's report will be broadcast on 60 MINUTES Sunday, Jan. 8 (7:00-8:00 PM, ET/PT) on the CBS Television Network.

Olga Urbani, whose company, Urbani, controls 70 percent of the world's truffle trade, takes Stahl out in the hills of Perugia Province, Italy, to hunt the "black diamonds" with a dog who finds them one at a time. "Very rich American people, they only see truffles on the table of a very elegant restaurant," she tells Stahl. "They don't see this. Now you know why they are expensive." Watch an excerpt.

Other countries, including the U.S., have tried to farm truffles to limited success. European truffles have an edge because the continent's red soil and rainy summers produce a more pungent variety sought by the best chefs. But they must be hunted and found when they are ripe, so they are collected in small amounts. "[Farmers] can't do anything," says Urbani, "You're always on the phone... saying 'Sorry, sorry, I don't have'... I wish I had 100 tons a day to make everybody happy."

Ecological changes have brought the truffle harvest down to just 30 tons a year from 2,000 tons 100 years ago. Prices are spiking as demand increases, causing a black market for truffles that resembles the shadowy world of illegal drugs, complete with thefts and murders. As bad as that is, dealers fear cheap Chinese imports, which look like the more expensive truffle from France but are a different variety altogether. "The Chinese truffle is boring... no taste, no smell," says the famous French chef and restaurateur known simply as "Bruno."