Sterility

Producing safe products is a core goal of all medical device manufacturers and sterility assurance is a key component in achieving that goal. Many single use medical devices are terminally sterilized by ethylene oxide or radiation methods such as gamma or e-beam. The FDA and other regulatory bodies requires that the sterilization process be validated and these validations typically require a bioburden and sterility testing. Sterility testing and bioburden testing are also performed on devices as part of routine quality control.

A bioburden test determines how many microbes are on the medical device. Before performing the test, a suitability test must first be performed. The purpose of the bioburden suitability test is to ensure that the bioburden test method is effective in recovering microorganisms that are present on the device and to show that the test method does not inhibit growth of the recovered microorganisms. To perform the test, a known number of microorganisms are placed on a sterile device and then removed using the same method that would be used for the actual bioburden test. If the bioburden test method was not able to remove a significant portion of the microorganisms on the device then the sterilization cycle or dose may be inadequate. Based on the outcome of the suitability test, a recovery factor is determined to account for the percentage of microorganisms that were not able to be removed from the device.

After the suitability test is complete, the device will undergo bioburden testing to determine their microbiological load. This device bioburden level is often used in sterilization validations to calculate the dose or sterilization time a device may need. Additionally, as part of quality control, quarterly bioburden testing is done to determine whether the microbiological load on a device has changed.

ISO 11137 Dose Audits

Quarterly dose audits are performed according to ANSI/AAMI/ISO 11137 and are done as a check to ensure that the sterilization process is still producing adequately sterilized products. All sterility testing is conducted in an ISO Class 5 environment.

The microbiology lab at Pacific BioLabs is experienced in preparing and testing a wide variety of devices, from small needles to large, complex devices. For large devices, Sample Item Portion (SIP) preparation may be necessary. This consists of cutting a device into pieces for testing, or selecting the most appropriate parts of a device for testing.