Methods are disclosed for sterilizing a selected portion of a product and for assembling a sterile product from two or more parts which can not be sterilized with the same form of sterilization. A sterile product produced by these methods is also disclosed. The method for sterilizing may include sterilizing a selected portion of the product by exposing the selected portion to an electron beam, while shielding the remainder of the product from the radiation of the electron beam. The method of assembling a sterile product from two or more component parts may include the steps of sterilizing the first part of the product, isolating a portion of the first part from the remainder of the first part, attaching the second part to the isolated portion of the first part, and exposing the isolated portion to a form of sterilization which is deleterious to the remainder of the first part, while shielding the remainder of the first part from such form of sterilization.