Methods of sterilizing a hollow fiber filter module, hollow fiber filter modules comprising closures and closures comprising an oxygen absorber are disclosed. A method according to the invention is distinguished in that the interior of the hollow fiber filter module is sealed off by means of the housing associated to the hollow fiber filter module and by means of the closures, and at least one of the closures comprises an oxygen absorber. A hollow fiber filter module according to the invention is characterized by the corresponding closures with or without an oxygen absorber.