How did mold, dead moths, and maggots end up in granola bars I bought from Target?

I don't think it was Target who did it. If they wanted to keep selling their products, they would be more careful. Someone probably put all the in the box then sealed it again to make it look like Target's fault. The probability of having mold, dead moths, tiny green inch worms, AND maggots is far to unlikely to be a mistake on Target's part.