Most commercial truffle oils are flavored with synthetic compounds such as 2,4-dithiapentane, one of many molecules that give Italian white truffles their distinctive aroma.
Pigs, trained dogs and goats are used to sniff out truffles, which grow below the ground.
Truffles produce a chemical almost identical to a sex pheromone found in male pig's saliva. Sensing this odor prompts mating behavior in the female pigs as they rut and try to get at the buried truffles.
Men also secrete this chemical in their underarm sweat.
The truffle has been described as: diamond of cookery, fairy apple, black queen, gem of poor lands, fragrant nugget, black pearl, holy of holies for the gourmet.
Truffles can cost between $800 and $1,500 a pound.
In 1892, French truffle production was about 1,000 tons. Today average production is below 100 tons.
People have been eating truffles for almost 4,000 years.