Very interesting point that it may well be pantry moths. I will note that even though pantry moths have a smaller yuck factor than maggots, infesting people's houses with pantry moths is an undesirable feature for a pet food.

What I can't figure out is whether anything is happening at all. The accounts at consumer affairs have what I'd call a plausible amount of variation, but if Purina dog food is apt to have lots of insects of some sort, why aren't I seeing complaints about it in more places?