Kind of depends on what you consider to be Long Term, and depends on what you like to eat.
I don't consider Freezer or Fridge. Figure, power out, it's the first to be used up. Probably a good month plus in there to start from. Little generator should last that long...
SHELF STUFF
I have 3 levels.
The Less than 1 year Pantry,
BUT it has 6 months worth of food that I TRY really hard to rotate. Including my GOSSNER milk from Dollar Tree good for 12 month shelf life and NUTS of any kind, which get funky and then turn rancid. Peanut M&Ms are nasty once they get old, lol
The 2-5 year level.
Canned goods, Keystone Meats. Extra jars of peanut butter, canned regular butter, canned cheese, tuna... stuff like that.
All those little mix things in a pouch like Stove Top, Mac N Cheese, Ramen Noodles, Cake Mixes, Ketchup, etc.
The 10-30 year stuff.
Dry Goods mostly. LDS #10 cans. 5 gal pails from Emergency Essentials and Augason Farms. Mountain House stuff, which the recently re-rated to 50 years if stored correctly.
SO... what area are you asking about?