sterilize

Sterilization is the process of eliminating or inactivating all forms of microbial life, including bacteria, viruses, fungi, and spores, on inanimate objects. Items that have been sterilized are considered sterile and are used in settings where infection risk must be minimized.

Common methods fall into physical, chemical, and filtration categories. Physical methods include moist heat, such as autoclaving (typically around 121°C at 15 psi for 15 to 20 minutes, or higher temperatures for shorter times) and dry heat (often 160–170°C for extended periods). Filtration physically removes microbes from liquids or gases using membrane filters with pore sizes around 0.22 μm. Radiation methods employ ionizing radiation (gamma rays, X-rays, or electron beams) to inactivate organisms. Chemical sterilants, including ethylene oxide or hydrogen peroxide gas plasma, are used for heat‑sensitive devices, while liquid chemical sterilants must be properly aerated and contact time is critical.

Validation and indicators are essential to demonstrate effectiveness. Biological indicators containing resistant spores are used to verify the process, supported by chemical and physical indicators and routine process controls. Sterilization is load‑dependent and must be validated for specific items, packaging, and containers.

Applications include medical and surgical instruments, implants, laboratory equipment, pharmaceutical manufacturing, and sterile packaging for foods and consumer products. Sterilization is distinct from disinfection and sanitization, which reduce or remove microbes but do not achieve complete sterility. Limitations include potential damage to heat‑sensitive materials and the need for thorough cleaning prior to sterilization.