However, the rumor that fast food never goes bad is just a myth. The truth behind why certain fast food items never seem to rot is simple. Most fast foods are high in salt and low in moisture. They dry out before they can grow mold. It’s the same reason why foods like beef jerky and beans last so long in cool, dry conditions.

This is the reason the fries didn’t go bad stated in the original Super Size Me documentary.

High salt foods are bad for you. Beef jerky is also bad for you