Keeping things fresh

My job runs off of 12 hour shifts, and many times gets kicked into overtime working sometimes 18 hours (I'm sure I'll have some 24 shifts as well in the near future). This means I potentially consume EVERY meal of the day out of the house and was hoping to get at least two of those meals as bentos or carry to work as opposed to eating out all the time. What are your best ideas for keeping things cool while driving (I am an EMT so will be in a vehicle all day with my lunch with me) that won't end me with a soggy lunch/dinner/snack?