Background information Edit
Art Department Coordinator Penny Juday had a prop bottle of Klingon ketchup made to feature in Quark's Bar on Deep Space 9 during the show's first season. (Star Trek: Deep Space Nine season 1 DVD special feature "Secrets of Quark's Bar")
In the Star Trek: The Original Series novel Traitor Winds, Nyota Uhura, Pavel Chekov and Hikaru Sulu are hunted by assassins and stow away aboard the partially-disassembled USS Enterprise. While hiding, they try to coax edible food out of an unfinished food synthesizer which makes for them a plate of tortellini, although in place of the normal tomato sauce, the confused machine provides the dish covered with ketchup instead.