First, make sure your food is vacuum packed. Does your airline carry dry ice? Of so ask the CC, very nicely, if they will store your food for you. When you want to eat make sure the CC don't need the aircraft ovens for the pax, again, if you ask nicely they may heat it for you.
You don't say type of aircraft or facilities available. What is so bad about crew food that you think you might get ill? (I ate it for over 36 years!).