When you depend on getting essential goods from overseas, most foods that had once been imported soon vanished completely from the grocer's shelves.
The ships that crossed the Atlantic during the war could only carry the most essential foods, such as flour for bread, and sugar for preserving fruits. So there were, for example, few oranges and no bananas at all for six years. Tea and coffee were thought of as essential foods. Milk was concentrated and put in cans, so was beef and pork – spam.
