A process for surface pasteurization/sterilization of particulate food products. Water uptake and qualitative changes of food products are minimized and pasteurization or sterilization conditions are optimized when food products are used preheated, wherein product temperature is selected a few degrees below the evaporation temperature of the pasteurization/sterilization system, in that the preheating temperature of food products is selected lower than the saturated steam temperature, preferably a few degrees below the saturated steam temperature at a predetermined pressure, in that treatment is performed in a moist, air-free atmosphere, wherein pasteurization occurs at temperatures between 55 and 99.degree. C. at a low pasteurization pressure, or sterilization occurs at temperatures between 100.degree. C. and 140.degree. C. at a higher sterilization pressure, in that heat treatment occurs for 1 to 30 mins, and in that the water of condensation is removed from the surface of food products by a subsequent vacuum drying at a further reduced pressure.