Cooking snack foods

Snack food is cooked by heating at least partially using electromagnetic induction a bed of particles 12 comprising magnetic and/or electro conductive material, and providing snack food pieces in the bed of particles such that the food is cooked by heat transfer from the heated particles. After cooking, the snack food and particles are separated, e.g. by sieving, size exclusion, density difference, vibration or gravity. Preferably the magnetic and/or electro conductive material is ferro- or ferromagnetic to allow detection and/or separation of the particles from the food after cooking using magnetic force. The particles preferably comprise or include steel or ceramic material, and may be ceramic or polymeric with steel parts or inclusions, e.g. hollow or core-filled spheres or near-spheres with metal walls, cores or inclusions. The particles may comprise first and second particles with different sizes and/or densities, and may have a size from 40µm to 5mm. The particles may have a monomodal or multimodal size distribution. The snack food pieces are preferably starch-based precursors which expand upon heating. The food may be cooked in a batch or continuous process, and the particles may be heated before or after adding the snack food.