My intention is to keep two cases (consisting of 12 Mainstay 3,600 calorie rations each) in our SUV. This provides over 30 days of minimal caloric intake for my wife and I.

Every five years I throw out the cases, and replace. I threw away my last two cases in August 2015, but have not replaced them.

Mainstay Emergency Rations are heat stable, meaning the heat of getting cooked in a car won't cause them to spoil. I've eaten one after storing it in a black SUV for 4.5 years. It tasted like oily cheap lemon cake, but no ill effects were had by me or Mrs. Architect.

ETA: If the packaged doesn't look "vacuum sealed" then throw out the bar - it has been compromised.