A customer recently contacted us detailing how positive biological indicators (BIs) were popping up in their Vapor Hydrogen Peroxide (VHP) process. The customer explained that they had no trouble with a square shaped room but when the configuration of the room changed (to an L-shaped room for example), they would experience unexpected positives. The positive BIs always seemed to occur in the same general area.
So what is wrong with the BIs?
Since the positive discs are showing up in the same general area of the room, it is most likely that the user may have a problem with the delivery of the lethal gas to some areas of the room. In this instance, the BI is doing exactly what it was designed to do, identifying the area of the chamber/room that is not receiving an appropriate dose of sterilant.
Mesa’s Technical Support team explained that the BIs are indicating that the circulation is not sufficient in this area in order to achieve the sterilization levels that the user is trying to accomplish. As is often the case for VHP sterilization, fans are needed in order to help the sterilant circulate throughout the more difficult areas to reach.
The BI Support team also pointed to the following documents from Mesa that have helped this user in redefining their procedures:
addresses Parameters Effecting Vapor Hydrogen Peroxide BI Performance
addresses Proper BI Placement During VHP BI Performance, and
addresses Using Replicate BI’s
For more information on VHP sterilization and BIs, please send any inquiries to firstname.lastname@example.org.
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