Happy Meal Project - Artist Photographs McDonald's Happy Meal For 137 Days

This will happen to any similar foods. I have done this experiment many, many times with meat & potatoes dishes accidentally left in the pan on the stove for a period of months. (You all are fortunate you don't have to live in my kitchen, we'll put it that way.)

By day two or three, what little water remained after cooking evaporates, and they visibly shrivel a bit. Six months later, they'll look essentially identical to day three.

Is it because of preservatives, artificiality, etc? No. I cut and peel potatoes, take the meat out of the meat box, and fry them (and onions) in a lightly oiled pan. No secret sauce required.

If you allow them to get and remain wet, you get a real science project on your hands.