How do you keep moisture out of the foods in a small office fridge?

I have a small fridge in my office. The kind that has the tiny little freezer and then some small shelves in it as well. I went and bought a bunch of snack stuff to put in there and like a week later everything was all wet, and moisture had ruined a lot of the food. How to I get rid of this moisture? There is not actually any moisture forming in the fridge (walls or roof), but everything is all soggy, and most of it is packaged items. I have sealed tortilla's that are just soaking wet, and expensive sealed cheese that is now gross because it has turned to mush. What can I do to fix this? I have checked the seals on the fridge and they are fine.