"Hitler will end up as a cheese"?
OK, I dont' understand the gag about Hitler and cheese. It occurs twice in the movie, first in the opening rehearsal, where the boy says that his father says that "They made a brandy out of Napoleon, they made a herring out of Bismarck, so Hitler will end up...", and the adjutant finishes the sentence with "Hitler will end up as a cheese", saying that it's "a natural thought", thus leading to Jack Benny questioning what he means by "a natural thought", followed by the adjutant's apoplectic response, ending with an round of "Heil Hitler!" from all three.
Then later in the movie, there's the scene with Tura (masquerading as the Professor) and Colonel Earhardt, basically repeating the above exchange, but with Earhardt saying the entire joke and then having to hastily try to explain what he means, ending with the Heil Hitler.
So my question, what's the deal with the cheese?