The process for sterilizing or pasteurizing a liquid (3) contained in a hermetically closed container, comprises transporting the container to a treatment zone in which the container is submerged in an external fluid flow, simultaneously heating the liquid by electromagnetic waves at a rate of greater than 30[deg] C per second up to a treatment temperature (T) of 20-66[deg] C and agitating the container, and applying a pulsed alternating electric field (5) and a pause to the liquid up to 10-100 microseconds for electroporation treatment depending on the value of the treatment temperature. The process for sterilizing or pasteurizing a liquid (3) contained in a hermetically closed container, comprises transporting the container to a treatment zone in which the container is submerged in an external fluid flow, simultaneously heating the liquid by electromagnetic waves at a rate of greater than 30[deg] C per second up to a treatment temperature (T) of 20-66[deg] C and agitating the container, and applying a pulsed alternating electric field (5) and a pause to the liquid up to 10-100 microseconds for electroporation treatment depending on the value of the treatment temperature. Total heat energy provided to the liquid by electric field pulse is less than 0.05 J/cm 3>；. The electric field has an oscillation frequency of 100-1000 KHz and a pulse repetition frequency of 10-100 Hz. Amplitude (E) of the alternating electric field in V/cm is given from the equation, C(T)= log (E +1)= B(T), where B(T)=-2.340x 10 ->； 5>；T 3>；+1.290x 10 ->； 3>；T 2>；-3.110x 10 ->； 2>；T+5 and C(T)=-4.503x 10 ->； 5>；T 3>；+2.888x 10 ->； 3>；T 2>；-5.900x 10 ->； 2>；T+4. The transport liquid is turbulized in rotation around the container. Static pressure developed in the treatment zone is created by pumping and locking system and by a liquid column constituting an external fluid overhanging in the treatment zone of the container. The transport fluid is water or water-bas
