It depends on the food. The "natural" cat foods have a shorter shelf-life, so it is important to read the info on the bag.Originally Posted by strange_wings
As for food going rancid, as long as it's reasonably sealed up it should be ok. The stuff sits in unheated and non air conditioned warehouses, sometimes for months. They do make the dry to tolerate that sort of storage. Humidity is the problem.
The other issue is not the food itself going rancid, but the fat residue left on storage containers. If the food is poured out of the original bags into storage containers, there is a fat residue left over and that can go rancid and/or grow bacteria. Also some plastic chemicals can leach into the food, and some of them may be leached more when fat is present.