An air curtain is provided across the top of a food warming table, such as is employed in cafeterias for keeping food hot for serving. An air stream flows across the top of the pans holding the cooked food, where it picks up heat, moisture and flavor components, and is continuously recirculated to form an air curtain. Which retards the outflow of moisture and heat from the surface of the food. Keeping a cushion of hot moist air on the food maintains it in a hot and moist condition. Additionally, the air curtain acts to keep dust and insects away from the food surface.