An optional visual pH color change confirmation could be made after 48 hours of incubation. If sterilization process has not been successful, culture medium will change to a greenish color first, and then to yellow during incubation at 37 ºC, thus showing the presence of living spores. If sterilization process is successful culture medium will remain blue after the incubation process.
7-day readout for visual confirmation by color change is optional and not intended to be routinely performed; it is an initial validation of the 4 hour-reading. Fluorescence results may be compared to the 7-day visual reading.
NOTE: if 7-day readout is performed, a humidified environment will be required to avoid medium dry out.
Instructions for use
1. Identify the Terragene® Bionova® BT110 SCBI by writing the sterilizer number (in case of having more than one), load number and processing date on the label.
2. Pack the SCBI along with materials to be sterilized in an appropriate package according to recommended sterilization practices. Place the package in those areas which are considered most inaccessible for the sterilizing agent (e.g., the center of the load and areas near the door).
3. Sterilize as usual.
4. After the sterilization process has finished, open the sterilizer door, wait five minutes and remove the SCBI from the package. CAUTION: Wear safety glasses and gloves when removing the Terragene® Bionova® BT110 SCBI from the sterilized package.
WARNING: Do not crush or handle the SCBI excessively, since this might cause the glass ampoule to burst.
5. Check the Process Indicator on SCBI label. A color change to green indicates that the SCBI has been exposed to Ethylene Oxide. IMPORTANT: This color change does not evidence the process effectiveness to achieve sterility. If the color of the Process Indicator has not changed, check the sterilization process.
6. Press the lid to seal the tube. Crush the ampoule contained in the SCBI with an individual ampoule crusher or with the ampoule crusher placed within the incubator´s incubation area. Then shake the tube down vigorously, with movements similar to those performed to lower the temperature in a mercury thermometer, until the medium reaches the base of the tube and soaks the spore carrier entirely. Finally, place the SCBI in the incubator.
IMPORTANT: Use a non-sterilized SCBI as a positive control at least once per day, when a sterilization cycle is run. The positive control ensures that correct incubation conditions were met; the capability of the medium to promote rapid growth; viability of spores has not been altered due to improper storage temperature, humidity or proximity to chemicals and proper functioning of Terragene® Bionova® Auto-Reader Incubators. Both, the positive control indicator and the processed indicator, should belong to the same batch.
7. Incubate the processed indicator and the positive control indicator in the appropriate Terragene® Bionova® Auto-Reader incubators for a maximum of 4 hours at (37 ± 2) °C for rapid readout.
NOTE: Holding time between sterilization and incubation should not exceed a 7-day period. Fluorescence detection by the reader (excitation 340-380 nm / emission 455-465 nm) means failure in the sterilization process. If no fluorescence is detected after 4 hours of incubation, the result is negative.
The positive control must give positive fluorescence readout. It is good practice to incubate a positive control for visual color change. If chamber relative humidity is unknown or < 35 %, continue to incubate the Biological Indicator for a pH color change result, since low relative humidity may increase the fluorescent readout time beyond 4 hours.