Since the times of the Greeks and Romans these fungi have been used in Europe as delicacies, as aphrodisiacs, and as medicines. They are among the most expensive of the world's natural foods.
The flavor of the truffle is directly related to its aroma. The chemicals necessary for the odor to develop are created only after the spores are mature enough for release, so they must be collected at the proper time or they will have little taste. This is the only sure indication that the mushrooms are ready to be harvested. That is why animals have proven to be the best means of assuring that the fungi collected will be flavorful.