Yeast is a microscopic fungus that is used in concentrated form in items such as bread and other baked goods, wine making, vinegars, cheeses, some vitamins and other packaged items. This form of yeast is "domesticated" yeast....yeast grown for these purposes. There is also another type of yeast...wild yeast. Wild yeast is in the air around us. It is what starts to grow and ferment on fruit that is left out. Wild yeast is what gives sourdough bread it's strong flavor. Wild yeast goes to work on leftovers in your refrigerator. For someone who is intolerant to or allergic to yeast, both types could possibly trigger a reaction. Both "domestic" yeast and wild yeast may also be problematic for persons suffering from intestinal overgrowth of yeast.
