VPHP BIOLOGICAL INDICATORS

Vapor Phase Hydrogen Peroxide (VPHP) Biological Indicators (BIs) are used to develop, validate and monitor ambient pressure VHP decontamination cycles.  The BIs are manufactured in a controlled environment that maximizes spore purity and cleanliness and promotes a monolayer of endospores over the surface of the stainless-steel carrier. These characteristics are critical for BIs designed for use in VPHP decontamination processes due to the poor penetrative properties of VPHP. Excessive spore piling on the carrier, or the presence of debris can create a barrier to the VPHP which may protect underlying spores resulting in non-uniform BI performance. 

Great Divide Labs Certificate of Analysis (CoA) is unique to the market in that it not only provides population and D-value, but also reports the parametric data and fractional zone collected during the test isolator cycles used for D-value determination. These data are useful to end users because all the parameters that affect the kill kinetics are displayed along with the fractional zone of the BIs.

ASSESING D-VALUES UNDER ACTUAL USER PROCESS CONDITIONS

Great Divide Labs is here to help give a usable D-value on Biological Indicators used in the process development and validation of ambient pressure vapor phase hydrogen peroxide VPHP. With the lack of standards and numerous emerging applications with VPHP, the D-value as reported by the BI manufacturer, based on a single cycle setup, is not particularly useful to the end-user. That is where Great Divide Labs can help. We can design a cycle to match your parameters in our VPHP Resistometer. Using your Biological Indicator of choice, we can perform testing using the actual use parameters you provide to calculate a D-value specific to those conditions. Testing is generally conducted using fraction negative method or survivor curve (direct spore count) testing is also an option. All data from the exposure, including PPM hydrogen peroxide, relative humidity and temperature will be expressed on the Certificate of Performance (CoP).

VPHP BIOLOGICAL INDICATOR QUALITY

BIs used for cycle development and validation of VPHP decontamination processes have gotten a bad reputation. Many end users tend to place blame for unexpected positives on the BIs. Over the last decade additional information has been presented on cycle development and key parameters affecting the kill kinetics of VPHP. There are limitations to VPHP, as it is not a true gas, but rather a vapor. Additionally, its use as a decontamination agent is conducted under ambient pressures and not in a vacuum. This limits its ability to penetrate which can be problematic with poorly made BIs containing excessive spore piling and organic debris. These features tend to present erratic results and tailing positives in the BIs. This is due to the time it will take the sterilant to penetrate through these unwanted features. Great Divide Labs can screen these poor performing BI Lots out so that end users can avoid costly down time due to investigations or having to rerun cycles. 

We also work with customers to set up and perform third party incoming inspection for VPHP Biological Indicator lots.

ENVIRONMENTAL/BIOBURDEN ISOLATE IDENTIFICATION AND RESISTENCE TESTING

Have a contaminant in your facility that you need identified or need resistance values for? We can assist with that as well as provide a liquid suspension of the isolate for you to inoculate selected areas and/or materials for testing in your production isolator. Send us a streak plate of the organism and we will identify it genetically, grow a crop from the isolate and inoculate a substrate of your choice. Resistance testing can then be conducted under your specific VPHP parameters. The results will be presented on a CoP.

BACKGROUND

We have been involved in the development, testing and manufacture of Biological Indicators for well over a decade. Most of that focus was on Biological Indicators used with Vapor Phase Hydrogen Peroxide. We have had the privilege to work with some of the pioneers to the VPHP technology along with many end users.