Which sterilization method cannot be biologically monitored?

Glutaraldehyde is primarily used as a high-level disinfectant rather than a sterilization method. While it can effectively kill a wide range of microorganisms, it does not achieve sterility under all conditions, particularly when prolonged exposure time may be required for certain types of spores. Biological monitoring, which involves using biological indicators that contain spores of specific organisms, is generally suitable for sterilization processes that achieve complete destruction of microbial life—like steam autoclave, ethylene oxide, and dry heat sterilization.

Glutaraldehyde's position as a disinfection method limits its applicability for biological monitoring, as there is no standardized biological indicator specific to glutaraldehyde that would confirm the destruction of all microorganisms, particularly spores. Therefore, in the context of sterilization methods, glutaraldehyde cannot be biologically monitored, recognizing its role primarily in disinfection rather than as a full sterilization process.