The decimal reduction time describes the amount of time required to kill 90 % of a specific microorganism. This time period is referred to as the D-Value. The determination of this D-Value is a mandatory requirement for the quality control of batches of biological indicators.
The D-Value determination determines the informative value of the biological indicators, which are subsequently used to verify the H2O2-based decontamination. The SKAN Laboratories team is experienced in the determination of the D-Value and performs all control procedures based on recognized standards.
- How many biological indicators are used for a determination?
The established test procedure of the SKAN Laboratories team requires around 101 biological indicators for a reliable D-Value determination.
- How is the inactivation state of the biological indicators evaluated?
After the H2O2 decontamination of the system, the biological indicators are placed in tubes containing 9mL Trypcase Soy Broth (TSB) and get incubated. The samples that are not completely inactive, turbid the TSB. A statistical evaluation of the tubes showing either growth or no growth provides the D-Value determination.