Biological indicators, and systems and methods for determining efficacy of sterilization

A method of determining the efficacy of a sterilization process, the method comprising:

• providing a biological indicator, the biological indicator having previously been exposed to the sterilization process, the biological indicator comprising:
• a plurality of spores deposited on a substantially planar spore carrier,
• a germinant container housing a germinant composition,
• a germinant pad, and
• a window,
• the germinant pad, the substantially planar spore carrier, and the window being in a stacked arrangement in the biological indicator;
• heating the biological indicator to an incubation temperature of the spores;
• placing the biological indicator in a BI bay of a BI reader, and using the BI reader to break a seal on an outer surface of the biological indicator, and to release the germinant composition from the germinant container into the biological indicator such that the germinant composition interacts with the plurality of spores on the substantially planar spore carrier;
• emitting light from an excitation source through the window of the biological indicator;
• exposing a camera at regular intervals to capture a plurality of images of the substantially planar spore carrier over time from light emitted back through the window of the biological indicator;
• and
• comparing the plurality of images of the substantially planar spore carrier to each other with respect to time to determine whether there is a change in the intensity of the light emitted back through the window of the biological indicator over time, the comparing the plurality of images over time comprising identifying an increase in a local light intensity over time at one or more discrete locations on the plurality of images, wherein an increase in the local light intensity over time is interpreted as survival of a spore and a failed sterilization cycle.

A method of determining the efficacy of a sterilization process, the method comprising:

• providing a biological indicator, the biological indicator having previously been exposed to the sterilization process, the biological indicator comprising:
• a plurality of spores deposited on a spore carrier,
• a germinant container housing a germinant composition,
• a germinant pad, and
• a window,
• the germinant pad, the spore carrier, the germinant container, and the window being aligned in the biological indicator;
• heating the biological indicator to an incubation temperature of the spores;
• placing the biological indicator in a BI bay of a BI reader, and using the BI reader to apply pressure towards the germinant container, the germinant pad, the spore carrier, and the window to thereby release the germinant composition from the germinant container into the biological indicator such that the germinant composition interacts with the plurality of spores on the spore carrier;
• emitting light from an excitation source through the window of the biological indicator;
• exposing a camera at regular intervals to capture a plurality of images of the spore carrier over time from light emitted back through the window of the biological indicator;
• and
• comparing the plurality of images of the spore carrier to each other with respect to time to determine whether there is a change in the intensity of the light emitted back through the window of the biological indicator over time, the comparing the plurality of images over time comprising identifying an increase in a local light intensity over time at one or more discrete locations on the plurality of images, wherein an increase in the local light intensity over time is interpreted as survival of a spore and a failed sterilization cycle.