one thing to remember for I worked up at the school from time to time and saw this happen way to often. Parents so often thinks that teachers or somone could warm up food in a micowave for thier child. Please do not think this without talking to the teacher as most of the time teachers has thier off period during this time, and there are way to many kids to warm everyone's lunch or whatever in the micowave.
For my gd's they like for me to do is to fix a deli tray for them. I get severa kinds of lunch meat and cut them into 1/4's and mix the meats together with cheese and crackers
fruit is always good to have in a lunch
weirners, vinessa saugages, boiled eggs, deviled eggs, egg sandwich,
even peanut butter sandwishes are good for them,