Ketchup doesn't need to be refrigerated. Lots of people do, but it's really not necessary. I've never seen it go green and fuzzy, and that includes spills outside that were there for weeks.

There are of course things that do, milk for example doesn't do well out on the counter for a couple weeks after you open the container of paramlait (as they continue to prove in the office every few weeks), but ketchup isn't one of them.

Salsa, on the other hand doesn't havethe same amount of acid in them, I've seen those go bad even in the fridge.