Pantry moth traps. Toss out all affected food. Install pantry moth traps. Keep cereals etc in plastic Tupperware-type containers. I had this problem years ago and solved it this way.
I get Pantry Moths in the warmer months (old apartment building problems) and these are great. They only kill the males, so if you still see some still flying around they are females but they can't make baby moths and they eventually just die. I just switch out the trap every 6 weeks or so.
Sucks. A lot of people I've known have had problems with meal moths in their pantries. These are the best solution if already infested, and sealed food containers are the solution if not.