Do you think the cig companies are gonna through out 100 pound bales of tobacco because of a little mold?
Right hundred pound bales... alls I can say is, the bales they use may be quite a bit larger then that. And it may get tossed if is doesn't meet spec. Lots of care may go into keeping it from growing mold from farm to cigarette.
Lots of steam is used as well. They also apply mold inhibitors. I would suspect most cigarettes have very trace amounts of living mold if any by the time you get em. Probably start off with trace amounts though. Also tobacco beetles like to eat up cured tobacco; those are mostly filtered out by the time you get to smoking a ciggy as well
Like others have said, I would toast it, nuke it, steam it real good before smokin' it if it's moldy. Personally I just cut the moldy bit off and use the rest of the leaf if it ain't too much.