Biological indicators (BIs) are crucial tools used in sterilization processes to ensure that microbial populations, particularly highly resistant organisms like bacterial spores, are effectively destroyed. Axis BIs provide direct evidence of the sterilization process’s efficacy by containing a known number of spores that are highly resistant to the sterilization method being employed. The most common types of sterilization methods include steam, formaldehyde, ethylene oxide (EO), and plasma sterilization.

AXIS Biological Indicators for Steam sterilization typically contain spores of Geobacillus stearothermophilus , as these organisms are highly resistant to steam sterilization conditions. After exposure to steam, the BIs are incubated under favorable conditions to allow any surviving spores to grow. If no growth is observed after the incubation period, it indicates that the sterilization process effectively killed the spores, providing assurance of sterility.