Testing of Biological Indicators (BIs)

BIs are tested in support of sterilization validations and routine product release for various sterilization technologies.

Our laboratory experts are equipped to provide product inoculation with biological indicator strips for a range of sterilization methods including steam and Ethylene Oxide (EO).

The biological indicator testing process is as follows:

  • BIs are filter strips impregnated with a known microorganism that represents the reference organism for that technology. E.g. Bacillus atrophaeus spores for EO, Geobacillus stearothermophilus for Steam.
  • General requirements for BIs can be found in ISO11138-1, with the specific requirements for EO and Steam in ISO11138-2 and ISO11138-3, respectively.
  • The product, with indicators attached, is subjected to the Customer’s preferred sterilization method.
  • The BIs are placed during validation to assess the challenge of the product bioburden to the sterilant and establish relationships between such and the BIs. Process Challenge Devices (PCDs) are often also used in this aspect of the validation.
  • Since such spores are usually challenging to sterilize, their presence/absence in the final sample validates the method or lot and determines sterility assurance levels (SALs)
  • The BIs can also be placed in during routine monitoring for product release.

The BI strips are removed from the product and sent to the STERIS to test for presence/absense of the microorganisms within the BI.

Product inoculation with biological indicators (BI)

STERIS can carry out the product inoculation with BI strips for various sterilization methods, including Steam and EO, conducted at the Customer’s facility, or at a STERIS sterilization facility.

STERIS offers:

  • Integrated biological indicator testing with EO validation and/or routine sterilization
  • Product inoculation with BI strips for evaluating sterilization process at Customer’s own site
  • Collaboration with Customers in Reduced Incubation Time (RIT) studies

Biological Indicator testing is used for validation and routine monitoring of :

  • Medical device sterilization
  • Pharmaceutical sterilization

Contact our team of experts to find out more about our Global Contract Sterilization, Testing and Validation Services.