Freeze dried dog food is actually made from fresh foods with nearly all of the water content removed through a special process. The result is a light and dry product that is packaged in air tight containers for future use. Freeze dried dog rations remain viable for years as long the packaging is not damaged or opened. This is because all micro-organisms need water to survive, so the spoilage process goes into suspended animation. When you’re ready to feed your pet, all you have to do is open the package, add a little water to reconstitute the food and Fido’s dinner is ready to be served.