Mold is a type of fungus that consists of small organisms found almost everywhere. They can be black, white, orange, green, or purple. Outdoors, molds play an important role in nature, breaking down dead leaves, plants, and trees. Molds thrive on moisture and reproduce by means of tiny, lightweight spores that travel through the air. You’re exposed to mold every day.
In small amounts, mold spores are usually harmless, but when they land on a damp spot in your home, they can start to grow. When mold is growing on a surface, spores can be released into the air where they can be easily inhaled. If you’re sensitive to mold and inhale a large number of spores, you could experience health problems.
Unlike bacteria that are one-celled, molds are made of many cells and can sometimes be seen with the naked eye. Under a microscope, they look like skinny mushrooms. In many molds, the body consists of:
- root threads that invade the food it lives on
- a stalk rising above the food, and
- spores that form at the ends of the stalks.
The spores give mold the color you see. When airborne, the spores spread the mold from place to place like dandelion seeds blowing across a meadow. Molds have branches and roots that are like very thin threads. The roots may be difficult to see when the mold is growing on food and may be very deep in the food. Foods that are moldy may also have invisible bacteria growing along with the mold.