A "sloppy joe" is a sandwich consisting of ground beef, onions, tomato sauce or ketchup, Worcestershire sauce, and other seasonings, served on a hamburger bun. There are several theories about the sandwich's origin.

Early and mid-20th century American cookbooks offer plenty of "sloppy joe" type recipes, though they go by different names: "Toasted Deviled Hamburgers", "Chopped Meat and "Minced Beef Spanish Style".

One theory of the sandwich's origin is that in 1917, Havana, Cuba, bar owner José "Sloppy Joe" Abeal y Otero created "a simple sandwich filled with ground beef stewed in tomatoes." This was possibly his interpretation of ropa vieja. His bar was reportedly frequented by Americans and Britons, including Errol Flynn, Ernest Hemingway, and Graham Greene.

Marilyn Brown, director of the consumer test kitchen at H.J. Heinz in Pittsburgh, says their research at the Carnegie Library suggests that the "sloppy joe's" origins lie with the "loose meat sandwiches" sold in Sioux City, Iowa, in the 1930s and were the creation of a cook named Joe.

References to "sloppy joes" as sandwiches begin by the 1940s. One example from Ohio is a 1944 "Coshocton Tribune" ad under the heading "'Good Things to Eat' says 'Sloppy Joes', originated in Cuba, you'll ask for more,The Hamburg Shop."

Food companies began producing packaged sloppy joe, in cans with meat, or just the sauce, such as "Manwich", by the 1960s.

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