Meals safe in danger zone I'm on campus for most of the day, and since eating on campus is expensive, I would bring leftover dinners with me. Since they would sit in my backpack for several hours before eating, I would use one of the many microwaves on campus to heat it up to kill any harmful bacteria that may be present.

I'm at a new college now, and there appears to be only one public microwave on the entire campus, which makes bringing leftover dinners inconvenient.

The Problem: The food I bring with me will sit around in the temperature danger zone for several hours before eating. Heating it back up and keeping it cool are not very feasible.

The Need: Meals that don't need to be kept cool or heated up. The only thing I can think of is sandwiches, and the only sandwiches I can think of are boring turkey slices on white bread. So, what kind of meals can I make then?
May I suggest investing in an insulated lunchbox and ice pack (decidedly un-sexy, but practical), or storing in a campus fridge?  These can extend length of time food is at a safe temperature considerably.

Thermoses are wonderful things; a good thermos that is filled with fully heated/cooled food and kept properly sealed will keep the contents out of the temperature danger zone for at least 4 hours.  The brand-name manufacturing site claims 6 hours in the safe zone for commercial products, with up to 16 for hot substances.  

Failing this, cheese or PB&amp;J sandwiches are pretty nonperishable.  Remember that cheesemaking was originally intended to preserve the nutritional contents of milk for prolonged periods without refrigeration, and harder cheeses stay safe for longer.  The catch is that they will exude some oil if kept warm.   A similar principle applied to heavily cured meats, which are treated with nitrites or smoked, allowing them to be safely kept at room temperature. 

A personal favorite meal for me is baguette, cheese, and a cured sausage.  If you want to go even simpler, you can have a quite satisfying meal with  a really good artisan bread and a dipping container of herbed/peppered olive oil.