
Mold spores are everywhere. Mold and mildew are types of fungi, microorganisms that depend on other organisms for sustenance. There are over 100,000 known species of fungi. The great variety of species means that patterns of mold growth and the response of mold in a particular situation can be unpredictable.
Molds excrete enzymes that allow them to digest organic materials such as paper and book bindings, altering and weakening those materials. In addition, many molds contain colored substances that can stain paper, cloth, or leather. It is important to realize that mold can be dangerous to people and can in some cases pose a major health hazard. Mold outbreaks should never be ignored or left to "go away on their own."