The real stuff, mind you -- introduced in 1937 in a Depression-thrifty effort to use pork shoulder, which wasn't selling as well as the rest of the pig, Wikipedia says it it was the first shelf-stable canned-meat product. (I'm not so sure -- the Brits had tinned "bully beef" during WW I, though it didn't get rave reviews).
First or not, Spam is tasty and showed up just in time to feed solders and civilians around the world during WW II -- the Brits and Russians welcomed it and so did our troops, despite giving it a number of mocking nicknames.
It's not a health food, no more than bacon. They make a low-salt version that's pretty good but the main appeal for me is that it's a meat product I can keep on the top shelf of the pantry for times when the fridge is bare and we're hungry. This morning we were out of breakfast meat and I started to reach for the Spam but hesitated: a whole can is way too much for breakfast for two.
Then I remembered: the "big-box" store sells little seven-ounce cans of Spam and I'd bought one. That's just about right for a two-person breakfast.
And it was. Hormel turned those hard-to-sell pork shoulders into some good food.
It's worth keeping some canned meat on the shelf. Most kinds are good for a couple of years and can make a snow day, a lazy day or a forgetful day better. Spam is a classic and good corned beef is well worth adding (some versions are quite salty. Rinsing them helps. Keep canned diced potatoes, too, and you can make your own corned beef hash, better than the pre-made versions). With a two-year rotation cycle, I don't know if you can call it "preparedness food," but it's useful to keep around.
Working On A Starship
3 weeks ago