Electromagnetic radiation with wavelengths just longer than visible light, perceived as radiant heat. In food processing, infra-red emitters transfer energy directly to food surfaces without heating the surrounding air, making it efficient for grilling, toasting, roasting, drying, and surface pasteurisation. Near-infra-red penetrates slightly below the surface, while far-infra-red is absorbed at the surface. The method offers rapid heating, compact equipment, and precise control, and it is often combined with hot air or microwaves in hybrid ovens. Engineers must manage uneven heating on irregular shapes to ensure every part of the product is safely and evenly treated.