A mold is a fungus that grows in the form of multicellular filaments. Molds are spread by spores which can be transmitted by air, water, or even insects.
Molds are known to cause respiratory problems and allergies, although in the right conditions, some molds can produce mycotoxins that can cause illness.
These procedures listed above enumerate the amount of mold present in a sample using a spread plate, pour plate, petrifilm or air sediment method.
Also see Yeast, as these tests are typically performed together.