What is the difference between sterilize and disinfect?
Sterilization and disinfection are both processes aimed at eliminating microorganisms, but they differ in the level of disinfection they achieve and their methods of action.
1. Sterilization
Sterilization is a process that completely eliminates all forms of microbial life, including bacteria, viruses, fungi, and bacterial spores. It is considered the highest level of disinfection and is commonly used in medical settings, laboratories, and certain industrial applications where absolute sterility is required.
To achieve sterilization, various methods are employed, such as:
- Heat: Dry heat sterilization or autoclaving involves exposing items to high temperatures (121°C or 250°F for at least 15 minutes) in a pressurized autoclave. This denatures proteins and destroys all microbial forms.
- Chemical sterilization: Chemicals such as ethylene oxide (EtO), hydrogen peroxide (H2O2), chlorine dioxide (ClO2), and peracetic acid (CH3COOH)2 can effectively sterilize equipment and surfaces. These chemicals have broad-spectrum antimicrobial properties and can eliminate bacterial spores.
- Radiation: Exposure to ionizing radiation, such as gamma rays, can effectively sterilize items without leaving chemical residues.
2. Disinfection
Disinfection is the process of eliminating or reducing pathogenic microorganisms on non-critical surfaces to levels considered safe. Unlike sterilization, disinfection does not necessarily kill all microbial spores, such as Clostridium difficile (C. diff) spores. It aims to reduce the risk of infection by targeting most bacteria, viruses, and some fungi.
Common methods of disinfection include:
- Chemical disinfection: Similar to sterilization, certain chemicals can be used as disinfectants, such as chlorine bleach, hydrogen peroxide, quaternary ammonium compounds (quats), phenols, and alcohol-based solutions like isopropyl alcohol (IPA).
- Heat disinfection: Boiling or steaming at temperatures above 80°C (176°F) for a specified time can be effective in disinfection.
- Ultraviolet (UV) disinfection: UV radiation can be used to disinfect surfaces and air, targeting the genetic material of microorganisms.
Summary:
- Sterilization achieves the complete elimination of all microbial forms, including bacterial spores, and is necessary for critical applications.
- Disinfection reduces pathogenic microorganisms to safe levels but may not eliminate certain resilient spores. It is suitable for non-critical surfaces.
The choice between sterilization and disinfection depends on the desired level of microbial control and the specific application or setting. Sterilization is essential in situations requiring absolute sterility, such as surgical instruments, while disinfection is sufficient for many everyday cleaning tasks to reduce the risk of infections.