Ad date unknown, but Spam was invented in 1937, and this ad calls it “new”, so late 30s to early 40s is my guess.
Curiously, the product has an almost joke reputation in parts of the world, but in others it is considered a delicacy or luxury. Receiving a can of Spam from a mainland-US friend would be a gag gift, but it is given as a real gift in some places. That seems to be a historical result of huge amounts of Spam delivered into pacific islands by the US during WW-II. Soldiers would give the cans to the local food-stressed populations, and to this day it is associated with liberation and freedom. From there it was integrated into national cuisines. Countries like the Philippines have picked up the ball and run, inventing new local variations, incorporating local flavor and spice profiles, and using it in genuinely creative ways in traditional dishes.
Then came Python. To its credit, Hormel played along and leaned into the fun, rather than sending attack lawyers. They even created special Spam cans for Spamalot.
Spam.
I don’t buy SPAM but I’m never sad when it shows up in various foods I order, I’m especially fond of Musubi. The salt content is probably my biggest gripe.
I got curious about the shelf life, given the notorious salt content. Internet sources are rather contradictory in that regard. Some sources say the quality of the product will decline notably after about 3 years on an unopened can, but it will remain safe to eat (assuming no damage to the can seal!), just not as pleasant. Other survivalist-type sources say it actually will spoil after 5 years or so in an unopened can, and can become unsafe.
Most seem to agree that the original product is higher quality than its popular “mystery meat” reputation.