When in doubt... corned beef in the old fashioned 'twist key' (not pull tab) type can.

Estimated to last 30 years or more. Perhaps indefinitely.

WWI style twist key cans were used in the trenches of Europe. Prized for their seal and durability.

Roughly 750 calories of protein and fat. Exactly what you need to survive one day. WWII labor camp victims often did hard labor on less than 700 calories.

Anyway, it's a viable option.