Twelve year old rice and beans? It sounds like it's time to start eating that up, and replace it with new--packed in mylar with oxy-absorbers. Gamma seals are great, for the buckets you're currently eating out of, but regular lids will do just fine, for storage. With the food sealed in mylar, it's fine to use buckets that formerly held non-food contents. I use buckets that formerly contained stucco and drywall mud. They clean up just fine.
Rik