What verifies that autoclave sterilization has occurred?

The verification of autoclave sterilization is most accurately indicated by a biological indicator. Biological indicators contain live spores of highly resistant microorganisms, typically Bacillus stearothermophilus for steam sterilization, which are placed in the sterilization load. After the sterilization cycle, these indicators are incubated to see if any spores survive. If the spores are killed, it confirms that the sterilization conditions were adequate, ensuring that the sterilization process was effective in eliminating potential pathogens.

While chemical indicators and heat-sensitive tape provide some level of confirmation that certain conditions, such as temperature and time, have been met during the sterilization cycle, they do not provide definitive proof that micro-organisms have been effectively eradicated. These indicators will change color or display a mark that indicates exposure to a sterilization process, but they do not prove that the environment was lethal to the spores. Therefore, the biological indicator is the gold standard for verifying that the autoclaving process was successful.