The 3M™ Attest™ 1261 Biological Indicator (blue cap) is designed for monitoring 132°C gravity displacement steam sterilization processes.
The presence of active Geobacillus stearothermophilus spores is detected by a visual color change (media turns yellow). The yellow color change indicates a sterilization process failure. The final readout of a negative result (media remains purple) is made after 24 hours of incubation.