Sweet potatoes need to be cured before storeage to prevent them from molding. Perhaps they weren't cured. Also putting them in a plastic bag could have stimulated the mold if they weren't cured. I'd cut off the mold and cure them by keeping them in a warm place until the new cuts dried over. Here's a link that tells you about it. http://www.lsuagcenter.com/en/...
Good luck!
Politicians are like diapers, they need to be changed often, and for the same reason.
