If I eat expired Reeses' or Kit Kats will it be harmful to me? Because I found a bag of them and the Reeses' expired May 2017, and the Kit Kats expire next month. Will i be okay if I eat them? Will anything harmful happen?
You should be completely fine. As long as the food isn't wet, it won't mold and nothing will happen to you. Even if you waited another 3 years or so, I doubt they'd become harmful.
