the solution is easy: just stop trying to micromanage everything
Allow some private vendors to take over school cafeterias. Maybe places like Subway, Arby's and fast sushi places that can serve good stuff.
I always walk to the Chinese place nearby that offers up 20+ choices of fish, meat, and veggies for which I can choose 4 and only pay $4.00. I don't get why school kids have to pay $3-5 for a nasty sandwich, a fruit cup, and skim milk.