Kathleen wrote:It seems better to store a large amount of food frozen to avoid contamination, or to get the food more often in smaller amounts because if it's replaced more often, there is less likely a chance that it will be contaminated.

Most (if not all) pellet manufacturers have a "freshness date" on their packaging. Most are fifteen (15) months from the manufacturing date (not the date you receive it).
The main enemies of any dry food storage are moisture, temperature, humidity, and pests (rodents, larvae, ants, etc).
If any of you haven't read about the Vittles Vault, I urge you to do so. Click
here to read about them. It seems to get rave reviews (from the research I've done).
The Zervo dispenser only holds 17.5 ounces of dry (food) pellets. It also keeps food fresh for approximately two (2) weeks.
I should certainly go through 17.5 ounces of food in two weeks. I should also go through the 20 lb bag (stored in the Vittles Vault) in less than ten months.
Upon contacting the pellet manufacturers customer service department this morning, I was assured that using these two products would be a completely safe, and effective way of storing and dispensing their pellets.
As an aside, the dispenser is not a "must have" item.......it is purely for convenience.