What method is commonly used to monitor the effectiveness of an autoclave?

The method commonly used to monitor the effectiveness of an autoclave involves using paper strips or vials containing bacterial spores. This approach leverages the principle of biological indicators, where the viability of spores from specific, heat-resistant bacteria is tested after a sterilization cycle. The standard spores used are from organisms such as Bacillus stearothermophilus, which are known to withstand the rigors of the sterilization process.

If the autoclave is functioning correctly, the extreme heat and pressure conditions will effectively kill the spores, indicating successful sterilization. If the spores survive, it suggests that the autoclave did not reach the necessary conditions for sterilization, prompting further investigation or maintenance of the equipment.

Other options, while related to microbiological monitoring or chemical testing, are not standard methods for evaluating autoclave effectiveness. Agar plates inoculated with viruses or DNA fragments do not provide a direct measure of temperature and pressure conditions required for proper sterilization. Likewise, vials of pH paper cannot assess the biological efficacy of the autoclave process, as they measure acidity or alkalinity rather than microbial lethality.