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Biological Indicator Testing

BI stripsThe robust and repeatable biological indicator testing procedures utilised at Wickham Laboratories are aimed at confining the certified population of spores on manufacturer’s biological indicators (BIs) using an extraction, heat shock and plate count method.  Our techniques have been developed over many years of working with end users and BI manufacturers alike.

The requirements and performance specifications of biological indicators (BIs) used to verify sterilisation or decontamination processes are set out in ISO 11138 series (Sterilization of Healthcare Products – Biological Indicators).  These processes include, but are not limited to, moist heat, dry heat, ethylene oxide sterilisation, low temperature steam and hydrogen peroxide vapour decontamination.  BIs consist of a standardised and homogenous population of bacterial spores that vary in type or number, depending on the sterilisation or contamination method in question, but are typically a 6-log population of Geobacillus stearothermophilus and Bacillus atrophaeus, with known resistance to the mode of sterilisation being monitored, (so called D-value).

We perform all of the standard methods of biological indicator testing, with many BI types including paper strips, stainless steel discs and a variety of self-contained BIs.  Our technicians have also assisted with bespoke BI production and enumeration projects, in order to determine susceptibility of a wide variety of microorganisms to decontamination processes as part of proof of concept work, publications and end product manufacturer claims.

We can also assist you with BI troubleshooting, and supply BIs and any media required for testing, whether conducted by ourselves on your behalf, or for in-house routine use.  We routinely offer validation and commissioning studies using BIs, particularly on autoclaves.  All biological indicators supplied and used in testing will be enumerated prior to conducting testing, to ensure suitability for use.

Please feel free to contact us us if you would like to discuss our bespoke or standard biological indicator testing services.