Mountain House freeze-dried foods are packed in airtight Nitrogen packed #10 cans. Up to 98% of the residual oxygen has been removed. Mountain House’s unique canning process uses both vacuum oxygen removal and nitrogen flushing. This is a time consuming and slightly more costly process…but well worth it. It is the same process mandated by the U.S. Military for whom Mountain House also sells to. Mountain House’s foods will have the longest shelf life available…up to 30 years! Mountain House has been around for 40 years so they know first hand. Each of Mountain House’s cans is coated with a protective enamel inside and out for double protection, including the lid. The cans contents are protected until you are ready to open and use them. After opening, we recommend using the contents within 1 to 2 weeks for best results and taste; using the convenient resealable plastic lid between uses. Treat any leftover food as you would fresh food.