Diacetyl is a diketone with a buttery flavor, commonly found in fermented foods and produced during the fermentation of certain bacteria. It is used as a flavoring agent in food products, particularly in popcorn and dairy. Diacetyl contributes to the aroma and taste of butter and is also a byproduct of the Maillard reaction in cooking. Its sensory characteristics include a rich, buttery flavor that enhances the palatability of various foods. While it is generally recognized as safe (GRAS) in small amounts, excessive exposure can lead to health concerns, particularly in occupational settings.