Abstract: The process is based on vacuum packaging a fresh food product such as unpeeled potatoes (3), sealing the package (1) by a transparent film barrier (2), film which and the package (1) are comprised of a material suitable to endure high temperatures and pressures, such as those that are reached when cooking the food product (3) in a microwave oven. The film (2) fastened by heat welding on a perimetric flap (4) of the package (1), has longitudinal valves (5) in order for the steam to come out during cooking. The food product or raw potatoes (3) are washed with ozonized water, before packaging them, allowing the preservation thereof without chemicals and permitting steaming due to the fact that said product or potatoes (3) are packaged with a certain minimum degree of moisture, since what really permits the cooking phenomenon is the moisture itself of the product, in the present case the potatoes that has been 80 and 85% moisture.