maxill u•tests BIs contain bacterial spores (Geobacillus stearothermophilus) on filter paper in a specially designed double walled ampoule. The unique design and culture media create a system that allows each BI to be used as the “spore test” or the positive control. The dramatic colour change identifies bacterial spore growth and allows you to easily identify a failed sterilization process.
Biological indicators are the most accepted means for monitoring of sterilization because they directly assess the procedure effectiveness in killing the most resistant type of micro-organisms which are bacterial spores. The bacterial spores used, G. stearothermophilus, are more resistant and present in greater numbers than common microbial contaminants found in the dental office. Therefore a inactivated biological indicator signifies other micro-organisms that underwent the same process have actually been destroyed, thus confirming sterilization.