The food synthesizer (aka food processor or, more colloquially, food slot) was a receptacle for synthesizing foods and beverages that were a commonly integrated into Federation starships and starbases in the 23rd century. Unlike the replicators of the 24th century, food synthesizers were seen as a supplement to a starship's chef.
In the standard Starfleet food slots 2260s, food orders were often made by inserting a record tape into a slot on the synthesizer, although voice command was eventually available. Even by the turn of the 2270s, the food synthesizer technology was questionable at best, with notable failures occurring aboard some vessels, such as the USS Enterprise. Some instance of food synthesizer malfunctions include an occasion when a food slot's voice command was disabled by a noncorporeal intelligence, causing the computer to carry out voice instructions unpredictably, or even interpret conversation among cremembers as meal requests. Eventually, synthesizer units stopped responding altogether, continuously producing meals, and filling a recreation room with food. (TAS episode: "The Practical Joker")
More mundane failures were common. On one occasion, patterns of flavors were reversed and strict carnivore Snnanagfashtalli was given a raw steak that tasted like avocado and Spock received a salad that was flavored as bœuf bourguignon. The two traded lunches. Spock shared his faux steak with Hikaru Sulu, who had received salmon that tasted like chicken and Marietta Cheung, whose duck lu-se-te tasted like wood chips in sugar syrup. (TOS novel: Enterprise: The First Adventure)