How Does Light Affect Bread Mold?

Because of the nature of bread and mold, most bread is likely to mold whether or not it is exposed to light. The actual affect that light has on bread mold varies based on the circumstances.

Mold 101

• Mold can grow on any surface as long as it has oxygen, moisture and organic matter. It does not need sunlight to grow, only the right components and the right temperature. Mold grows best in dark, dank places without air flow.

Sunlight

• Light and air-flow can help prevent the growth of mold in the home. But if your bread is in a bag and you place it near sunlight, the light will heat up the bread and cause it to release moisture into the bag. Moist bread is an ideal environment for growing mold.

Heat

• As you may have noticed, mold grows well in warm, wet environments. The ideal temperature for mold to grow is 80 degrees Fahrenheit. Mold is primarily made of water, so it must remain wet to grow.

Light and Growth

• Molds don't need light to grow because, unlike plants, they do not produce their own food. But at some point, most molds need light to reach later stages of development such as making spores. For this reason, light might increase mold on bread.

Labratory Lights

• Most lab-produced (for medical purposes) mold is grown in the dark. Light can have a drying-out effect on mold in general, as long as the light source isn't creating further growing conditions, as in moist bread.

Prevention

• The best way to prevent mold on bread is to make sure to keep it in a cool, well-ventilated area. Many commercially processed breads today contain chemical preservatives that help resist mold. Light will not necessarily prevent the growth of bread mold, but if you are just curious to find out how much mold you can grow, it might be a great way to increase your product.