Test intervals are selected to characterize the time that the test material would be effective in significantly reducing microbial counts during use (generally 0, 24, and at times 48 hours). The test is performed with treated and non-treated swatches of the test material. The non-treated swatches serve as a positive control for the test.
A test sample is placed into a sterile container or petri dish and inoculated with 1.0 mL of the appropriate test organism suspension at approximately 10 6CFU/mL. The sample is allowed to sit for the selected time and is then extracted in a neutralizer media which is diluted and plated accordingly. This is repeated for all test intervals using both the treated and non-treated material.
Organism recovery from the treated and non-treated materials is then compared to determine the log reduction and percent reduction over time.
Finally, a neutralization study is completed for the organisms and sample treatment types submitted to demonstrate the ability of the media to support organism growth.
“Nelson Laboratories is very organized from first meeting to discuss testing requirements and recommendations to receipt of materials which have been tested. Nelson Laboratories staff is very knowledgeable of the standards and test requirements.”
Mark , Quality Assurance , Medical Device Manufacturer
SAMPLE REQUIREMENTS: Samples may be submitted in sheets, or pre-cut into 48 x 48 mm squares or 48 x 48 mm diameter circles. A test sample consists of the number of squares required to hold 1.0 mL of inoculum. Samples may be tested as a single replicate, in duplicate, or triplicate.
The standard recommends duplicate samples be tested at each interval. A non-treated sample is also required to act as a positive control for each test interval.