MILDEW... Damaging and Discoloring Fungi

In this article, we will discuss the general issues of mildew growth on textiles. Due to space limitations, discussion of mildew-related health issues will be limited.

TT Mildew

What is Mildew?

Mycologists, scientists who study fungi, use the term "mildew" only for fungi that grow on plants. So, when mycologists say "mildew," they mean the white growth that causes diseases on plants.

People who are not scientists use the term "mildew" differently. For them, mildew is the discoloration caused by mold. The molds that grow around windows or in bathrooms are called "mildew."

Mildew is the common term used to describe a downy or furry growth on the surface or organic matter, caused by fungi, especially in the presence of dampness and decay. A fungus may be any of a large number of microorganisms that are parasites feeding on living organisms or dead organic matter.

Mildew stains typically range from gray to black in color, though other colors are also possible.

What Fibers are at Risk?

Microorganisms need organic materials to supply nutrients and, therefore, fabrics composed of natural fibers are potentially at risk. As mildew grows, it creates enzymes, which digest the fibers on which it is growing, causing permanent fiber damage and weakening.

Plant materials (cellulose-based), such as cotton, rayon, linen, sea grass and sisal are particularly susceptible to attack by mildew-causing microorganisms.

Animal fibers are more resistant to mildew growth than plant fibers. Pure silk is less susceptible if completely de-gummed. Wool decays only slowly but chemical and mechanical damage during processing can increase its susceptibility.

Inhospitable materials, such as synthetic fibers, are not immune from fungal growths but how they support these growths is not fully understood by biologists. It is well known, however, that clean fabrics are less likely to mildew than soiled ones.

Because most synthetic fibers, such as acrylic, polyester and nylon, are resistant to mildew, clean fabrics of these fibers will not support mold growth. But even on these fabrics, soil may supply food to start mildew. Cleaning fabrics on a regular basis helps prevent them from mildewing.

Tough Stains

It is important to understand that when there is mildew there is fiber damage. The only question is how much fiber damage has already taken place.

The first step is to get the fabric dry and eliminate the source of the moisture that fuels the problem. This will at the very least stop any further damage to the affected fibers. Beyond this, corrective measures are best left to professionals.

Few fabric stains are tougher to remove than mildew. Most importantly, mildew should be treated as quickly as possible. If not, it can spread quickly and do irreversible damage to the fibers.

There is a chance of removing mildew stains when they are new, relatively small, and close to the surface. There is little chance once they have spread and set into the fibers.

Resist the urge to treat mildew stains with household bleach (a commonly recommended procedure). Bleach attacks textile dyes and can also weaken or destroy many types of fibers.

Trust Fiber-Seal

As mentioned above, mildew stains can be very difficult to remove. The Fiber-Seal experts can advise you in specific situations where mildew has occurred, making sure that procedures are safe for the particular fabric involved.

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