We had a similar problem when I was at college. But it was the past tenants and they had been out of the apt for the summer and they took over all our cereal and dry foods. It was so annoying we had to get rid of everything, then they sprayed and then we had to clean, clean, clean. then we could go get more food. The guy said that it usually happens w/ products already at the store, especially at discount stores b/c they have been there for a while. We were in college so we all bought things cheap. But the guy also said that just b/c it happens more at discount store don't think that just b/c it cost more that it won't happen at other stores. GREAT. we can't ever win. The freezer is good idea but you might want to try another store. If one bag has it it could be possible that others do too.