Electron beam sterilization of contained liquids

A method for sterilizing containers of liquid by electron beam ionizing radiation wherein the depth of the liquid in the container may be greater than that penetrable by the electron beam. The container of liquid is exposed to an electron beam so that the microbial bioburden in the fraction of the liquid penetrable by the beam is reduced. The liquid is mixed by agitating or rolling the container either simultaneously or successively with the irradiation until the microbial bioburden in the entire volume of liquid is reduced to the point where the liquid is sterilized. An apparatus for carrying out the sterilization method is also disclosed. The method and apparatus may be used to sterilize liquid medical products.