According to research, bread can become moldy if it is not stored properly. Two of the big agents in the molding of bread is, exposure to air and being stored in warm, moist environments.
We learn from the Bible that bread is a type of the word of God (see Deuteronomy 8:3; Isaiah 55:10; and Matthew 4:4). So, if bread is a type of the word of God, perhaps we should watch out for agents that would work to mold or corrupt the word of God.
The first molding agent that was mentioned is that of air penetrating into the bread. Air penetrates through openings or gaps. Does your Bible have any holes in it? Say, like verses missing? Most of the new versions have left out approximately 17 verses. Does your Bible have Matthew 18:11? Maybe it has the verse, but check the footnotes. Does it have a note saying that this verse does not belong? The absence of this verse as well as the other 16 might be holes that would cause your bread to be moldy.
The second molding agent that was mentioned is improper storage. Is it possible that the bread you hold in your hand has had some improper storage in warm, moist conditions. It is stated by Bible believers and modern version defenders alike that the Sinaiticus, which is one of the main manuscripts used for the production of modern versions, was found in a can that contained trash waiting to be burned. Sounds like a warm, moist environment that could cause the bread to become moldy.
Joshua would have done well not to make league with those carrying the moldy bread (see Joshua 9:1-6) and perhaps we should learn from his mistake.