Soft, moist white bread is a prime target for mold growth. The green, odorous slime begins as small spots on the outside surfaces of bread, but quickly spreads, covering the entire loaf.
Mold is a fungus like mushrooms, according to Experiment Resources website. It feeds on organic materials, such as bread, food and plant matter. Bread mold is usually green and may cause infections, especially in those with respiratory illnesses or compromised immune systems, advises Mad Science website.
Bread mold thrives in warm, moist conditions. It is slower growing in the refrigerator. Breads with a low water content grow mold more slowly than moist breads. Most commercial bakeries include mold inhibitors, such as calcium propionate, in their breads. Homemade or organic breads mold more quickly because they lack chemical additives.
Mold grows on white bread within two to seven days, depending on the environmental conditions and ingredients of the bread. Bread is best used immediately or frozen.