Conventionally, there have been used various methods for sterilizing medical devices, which perform a sterilization process at an elevated temperature, such as a dry-heat sterilization process and a high-pressure steam sterilization process. Recently, some medical devices have been put to practical use, in which at least a part thereof is made of material with low heat resistance according to a diversification of the devices and those devices need to be sterilized at a lower temperature. Also, for devices with elongate hollow tubes such as endoscopic instruments, the interiors of the elongate hollow tube thereof should be sterilized.
To meet the requirements, there have been known a sterilization method in which a sterilization object is received within a reaction container, vacuum is introduced in the reaction container, and then the sterilization agent is injected into the vacuum, causing vaporization and expansion of the injected agent and then allowing the vaporized agent to enter the interior of the elongate hollow tube, which sterilizes the interior of the tube in its entirety in a low temperature environment.
In this sterilization method, hydrogen peroxide is typically used as sterilization agent. However, the hydrogen peroxide by itself may not be satisfied for the sterilization of the medical devices which always need an advanced sterilization. To counter this problem, there has been known a method which uses peracid agent including at least peracetic acid, as a sterilization agent, which is capable of exerting an advanced sterilization effect even with a relatively small amount thereof.
For example, patent documents 1 and 2 disclose a sterilization method which is designed to obtain an advanced sterilization effect by applying plasma in the sterilization process in which the agent is vaporized in the vacuum as described above.