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The Definition of Mold Spores

Chris Anzalone

Molds exist all around you. In most cases, they remain unnoticed, but under the proper environmental conditions, their tiny reproductive structures, called spores, can begin to germinate and multiply. If you understand mold spores, you can better identify, prevent and remove them.

By actively working to keep mold under control, you can save thousands of dollars in removal costs.

General Definition

Mold spores are microscopic, multi-cellular organisms that reproduce asexually. Molds are fungi, similar to yeasts and mushrooms, and they can grow in any environment with a constant source of moisture. During the growth process, mold spores begin to undergo chemical reactions that allow them to devour nutrients and multiply. These chemical reactions cause fumes to be released into the atmosphere. These fumes are responsible for the musty mold odor.

Mold vs. Other Fungi

Mold spores are similar to other fungal spores in many ways: they are airborne, they germinate when bonded with moisture and their cell walls consist of a substance called chitin (also found on the exoskeletons of arthropods). There are also key differences. Mold spores multiply by producing reproductive hyphae, whereas yeasts, for instance, do not produce these filaments. Also, mold can grow on almost any porous surface, which does not apply to other fungi.

Mold Types

Many varieties of mold exist. In fact, there may be as many as 400,000 types, according to Advanced Mold Inspections. Airborne mold spores can pollute the airways, causing severe allergic reactions in people with mold allergies. They can also cause sinus infections, respiratory infections and a lung inflammation known as hypersensitivity pneumonitis. Certain mold spores, like the Stachybotrys atra variety, also produce mycotoxins, which can cause severe illness or cancer, according to the Environmental Protection Agency.


Mold spores can only reproduce for as long as moisture exists. If, for example, you have a damp cloth with mold, you can neutralize the mold spores simply by drying the fabric in the sun. You can never fully kill a mold spore, but you can render it dormant. Even if you attack spores with powerful compounds with bleach, the spores can still germinate again if moisture returns. For this reason, cleaning mold is insufficient for removal. You must remove the spores and prevent excess moisture from accumulating in your home.