Process, and system, for sterilization of a product constituted by a non-distilled or demineralized liquid solution (3) contained in a rigid and/or flexible container (2). The process provides for at least one step of heating via capacitive supply of high-frequency current, with electrodes with facing surface of a closed-circuit electrode system (1) on the product, followed by a step of cooling with interruption of the supplied current during at least part of the heating step, a counter-pressure pressure (P2) is supplied and acts inside the system (1) and on the product being treated.
