Mountain House products are freeze dried. Freeze drying is a different process than dehydrating. Dehydrating leaves more water in the final product than freeze drying. Therefore, I believe the shelf life of dehydrated products may not be as long. Freeze dried foods have about a 30 year life.
Mountain House is not my favorite. Peak Refuel is probably my favorite. Other freeze dried brands are:
Alpine Aire
Backpacker's Pantry
Good To Go
Mary Jane's Farm
Packit Gourmet
Stowaway Gourmet
Hawks Vitals and Heather's Choice I believe are dehydrated.