Bionova® BT200 Rapid Colorimetric Reading Biological Indicators for steam were designed for the simple evaluation of the processes of Steam sterilization. The system contains a tube with a conical base and a filter special that allows to keep the glass in the upper part of the tube. A Simple reading can be accomplished using the color reference chart. If the sterilization process was not successful, the indicator medium will change from purple to gray-green and finally to yellow after incubation at 60±2 ºC, indicating the presence of live spores of Geobacillus stearothermophilus ATCC 7953. If the process is successful, the indicator medium will remain purple after the incubation. The final reading should be done after 8 hours of incubation at 60±2 °C.