My favourite option for fallout shelter food would be a mixture of lifeboat rations and chocolate bars and orange juice.

All can be consumed with no preparation or need for cooking or heating. Tinned tuna can be eaten straight from the can.

In the longer term, freeze dried foods like mountain house could be most useful, but not perhaps in the initial stages of a radiation emergency.

I would suggest a months stock of foods that need no heating or preparation of any kind, and another years stock of foods that need a bit more preparation.

Water is vital, keep a months worth of bottled water or long life fruit juice that can be consumed with no treatment or preparation.

If you must have coffee, I would suggest a stock of the ready made self heating canned coffee.
In a cold climate, the self heating canned foods might be worth stocking, both are rather expensive though.
Make certain that any such use a chemical reaction between quicklime and water, and not form of combustion.