I think it would really add to the immersion if food would go bad if it is not kept in proper condition. Creating a 'shelf life' would force characters to have to hunt more and not rely on amassing huge amounts of food - this is one thing that is always easy to get.
This would force the player to hunt more or return to villages more to restock - effectively limiting the amount of Fast Travel that can be used if you do not have enough food to make the trip.
Just a thought....