Facts about mold:

Molds grow over many surfaces, for example wood and food. Mold grows best in warm and moist temperatures, but some molds can grow at freezing temperatures. Mold is used to make cheese.

Humidity and temperature must be stable enough to foster the growth of mold colonies, often seen as a downy or furry coating growing on food. Molds reproduce through small spores.

Bread that is kept in warm moist environments is prone to the growth of mold. It becomes stale more quickly in the low temperature of a refrigerator, although by keeping it cool, mold is less likely to grow.