Moldy bread! where did that come from? moldy bread indicates that a fungus is growing in and on your bread. but how did it get there? the bread was in a plastic bag.
a) the mold or fungus waist the bread all along but it could not be seen.

b) mold spores are in the air around us. some settled on the bread when it was unwrapped.

c) the bread was stored near other food that contained mold and the mold was transferred by contact.

d) people carry mold on their hands and if someone touched the bread before washing their hands, they caused the mold to form.