Bacillus stearothermophilus endospores are used to test what?

Bacillus stearothermophilus endospores are used to test the efficacy of sterilization processes, specifically in autoclaves. These endospores are highly resistant to heat and can survive extreme conditions that would typically kill most other microorganisms. When subjected to the high temperatures and pressures of an autoclave cycle, if the endospores can be killed, it serves as an indicator that the sterilization process was successful.

Using these endospores in testing ensures that equipment and substances that require sterilization are effectively treated, as the presence of viable spores after an autoclave cycle would indicate inadequate sterilization. Other options, like testing pH levels or chemical resistance, do not utilize endospores in the same manner to validate the efficiency of a thermal sterilization process. Thus, the use of Bacillus stearothermophilus endospores is specifically focused on validating temperature-dependent sterilization methods.