Abstract: A process for controlling the microwave heating of a product to a temperature which is higher than or equal to a determined temperature for a period which is longer than or equal to a determined period, a marking support and a receptacle for product intended for such a control. Measurement is made of the resistivity of a thermally crosslinkable ink filled with conductive particles, with which the product or the receptacle containing the product has been previously marked and the resistivity of which is arranged to decrease in a predetermined manner in relation to the temperature and the period of microwave heating. The invention is applicable especially to the control of the sterilization of a pharmaceutical or agri-foodstuff product.