Does Light Affect Growth of Mold on Bread?

Does Light Affect Growth of Mold on Bread?. Mold growing on bread is a common problem, causing waste of food in both residential and commercial establishments. There are many factors that affect the growth of the mold, including temperature, moisture and light. Mold, which is a fungus, grow best in dark, warm and humid conditions.

What is Mold?

Mold is a fungus similar to mushrooms or toadstools. Molds thrive in moist, low light conditions, taking hold on organic material, including food products. Mold is essential to our ecosystem, as it breaks down dead organic materials to recycle the nutrients back to the earth. However, most people do not appreciate this vital function when they find it has invaded the bread in their pantry.

Common Types of Bread Mold

There are several different types of mold that commonly grow on bread. The most common is the "black mold" scientifically known as Rhizopus stolonifer. Another common mold is the Penicillium mold, which can be green, gray or white. Penicillium is the genus of mold the antibiotic penicillin was isolated from.

Growth of Bread Mold

Bread mold spores are common and can be found on just about any surface and any condition, including counter tops exposed to daylight or dark corners of a pantry. This can be demonstrated by touching a slice of bread to a counter top or other open area, then placing it in a bag to keep the bread moist. After a few days mold spores will begin to grow. The individual spore germinates to form hyphae, which grow into the mature fungus. This consists of rhizoids, which hold the fungus to the organic material and ingest the nutrients to help the mold continue to grow. The sporangiophore grows from the rhizoids and supports the sporangium, which is where the small spores grow and are released.

Effect of Light on Growth

Mold does not need light to grow, as one might think. Remember, mold is not a plant, it is a fungus. Plants need light to produce chlorophyll which is needed for the plant to make food. Fungi however do not have chlorophyll and do not make their own food. Fungi get their food from the organic material on which they are growing. Therefore, light does not have a direct effect on the growth of the mold. Light can have an indirect effect in increasing the temperature, therefore increasing the growth of the mold, and drying out the bread, therefore decreasing the growth of mold, since the mold prefers a moist environment.

Ways to Protect Your Bread

Bread containing preservatives will have a longer shelf life. Therefore, mass-produced store-bought breads will ward off mold growth longer than fresh baked breads. Storing bread in the refrigerator or freezer will delay the growth of mold, since mold grows best at temperatures between 75 and 85 degrees F. Do not keep bread in a bread box, as this creates a dark and humid environment, a haven for mold spores. To avoid losing your bread to mold, enjoy it while it is fresh.