I am not sure I see the need for these specialized food items. I sprinkle Clif bars throughout my packs, along with Tonka bars and beef jerky. One feature of these brands is very robust packaging - others have this as well. When you go this route, you can choose flavors that actually appeal. Where weight and bulk is not a consideration, I go for canned goods that get recycled periodically.

Recently, I found a beef jerky package that had an expiration date in 2005. It tasted just fine - no digestive problems, although I wouldn't recommend keeping anything that far beyond its date as a general rule.