I think if you leave snocones, they will melt. Never done it myself, but have heard that will happen. Otherwise, as Liza already mentioned it should be fine unless you have piggies wandering in the same area.
Sno-cones will melt and other food will get nommed by piggies. ^_^
Otherwise if it's going away and you've had visitors, it's the visitors taking the stuff!
As others have said the only real threat to the food on your floor are little piggy bandits who will come running up and chomp down on your tasty treats. I suppose if you are not careful with who you let into your house, you can end up with people who choose to act like little thieving piggies as well.