Mushrooms have been eaten in Europe, Russia, China and Japan for thousands of years. Through their history they have been thought to have had certain magical powers or have been used as medicines. There are over 250 edible mushrooms throughout the world. Although only a few are commercially available here the variety is increasing. Mushrooms will supply you iron, fiber and some B group vitamins. Stock is the strained liquid that is the result of cooking vegetables, meat, or fish and other seasoning ingredients in water.