What makes freeze dried food last longer?
Microorganisms and enzymes cause food to spoil, ripen, or rot. Freeze drying removes the water from food, so the microorganisms and enzymes can’t reproduce or react to degrade the food. Oxygen absorbers further preserve the food from their own enzymes that would cause it to ripen or spoil.
Sources:
http://science.howstuffworks.com/innovation/edible-innovations/freeze-drying1.htm
How long will freeze dried food last?
Freeze dried food can last between 20-30 years. The shelf life depends on how it is stored. Both the container and the surrounding temperature affect the shelf life. Cooler temperatures and non-porous containers will preserve the food longer.
Sources:
http://foodassets.com/info/bulk-food-shelf-life.html
https://www.thereadystore.com/food-storage/2813/an-in-depth-look-at-freeze-drying-the-origins-and-process/