Quantitative Carrier Test Method
Virox Technologies believes in delivering infection control solutions that are effective and provide the end users with germicidal data they can trust. When Virox created Accelerated Hydrogen Peroxide, we evaluated the currently accepted methodologies for generating germicidal efficacy for government registrations. The accepted methods are based upon the Association of Official Analytical Chemists (AOAC) standards set out some 30 years ago. Virox was also aware of the work being done by Dr Syed Sattar and the Centre for Research on Environmental Microbiology (CREM) at the University of Ottawa. Dr Syed Sattar has developed a new testing methodology called the Quantitative Carrier Test (QCT). Virox chose to utilize this new methodology to generate its germicidal data for Canadian government registrations. Why? The answer is clear. The QCT is positioned to become the new global standard for germicidal data generation. To understand the QCT and it's future role in germicidal testing one must understand its development. In October of 1990 the United States General Accounting Office issued a report to the US congress titled "EPA Lacks Assurance That Disinfectants Kill Germs" (available at http://161.203.16.4/d48t13/142318.pdf)
This report highlights concerns over the use and reliance of the AOAC testing methods for registering products in the USA. The reasons for this concern were based upon recognised deficiencies in the AOAC tests and how they might provide data that was not reliable. One outcome of this report was that a new testing methodology must be created to bring back confidence in the registered products sold to the marketplace. The EPA commissioned several labs to develop a new test to deal with the current deficiencies. The current AOAC testing methods have various deficiencies in their design including:
- Diluent & Soil load not specified
- 'Official' status revoked for some
- Contact time too long
- Inappropriate surrogates
- Diluent not standardized
- Soil load may not be used
- Neutralizers inappropriate
- Labour-intensive
- Lack of quantitation & reproducibility.
CREM was successful in the development of a better method with the QCT. The QCT effectively addresses concerns with the AOAC tests. Some of the features of the test are:
- Fully quantitative with no organism wash-off
- Delivery of precise volumes of challenge organism(s) & test formulation
- High degree of reproducibility
- A 'universal' three-component soil load
- Filtration reduces reliance on neutralizers
- Fewer test/control carriers than in the AOAC test.
The QCT test has become a American Society for Testing Materials (ASTM) standard #E-2111 and #E-2197 and is currently being reviewed by the EPA. Virox Technologies is pleased to see that the QCT test is quickly becoming recognised as a viable alternative to the AOAC methods. Decision makers can also feel confident that Virox products are meeting the needs of the 21st century by using more stringent testing methodologies for germicidal efficacy data generation.
QCT Presentation (pdf doc)