How was food pereserved in World War 2?

Answer 1

Pretty much as it is now - canned, frozen, dehydrated. Many housewives with a garden and farm wives "put up" vegetables in Mason jars for future use, a process much encouraged by the government. (People were exhorted to plant "Victory Gardens" in their yards to grow their own vegetables). Some such home "canning" requires sugar, which was rationed, but an application could be made for an extra allowance, which was routinely granted. Its said that canned food was invented for Napoleon's army.

There is an interesting chapter in Studs Terkel's collection of oral histories, "The Good War", about a man who had bought three empty, disused industrial plants, as a speculative investment. As soon as the war started the government hunted him down, and basically insisted on putting him into business in his empty factories. They gave him a choice of producing either frozen food, or dehydrated food, which was called "dessicated" food, except by the troops who had to try to add water and eat it, who called it "desecrated" food. The man chose poorly, and went with the dessicated food, and after the war learned that no one who had been in the service would tolerate the stuff in their house. Meanwhile Mr. Birdseye choose well, going into the frozen food end of it, and after the war making a tremendouns fortune selling Americans "TV dinners".