Sterilization indicators are devices used to validate and verify sterilization processes. They allow assessment of process effectiveness, confirmation that products have been exposed to sterilization conditions, or simply marking items that have been sterilized.
Depending on type and purpose, sterilization indicators are divided into two main groups:
- Biological sterilization indicators
- Chemical sterilization indicators
These consist of standardized bacterial spores inoculated on different types of supports, which not only allow proper use but also emulate the process that leads to microbial inactivation.
The purpose of these indicators is to assess the effectiveness of the sterilization process, i.e., the successful killing of vegetative microorganisms or spores.
Bacterial spores used in biological sterilization indicators are selected by species, population, and resistance to specific sterilizing agents, such as:
- Steam
- Ethylene oxide
- Hydrogen peroxide
- Dry heat
- Radiation
- Chlorine dioxide
- Formaldehyde
They are available in various forms, including:
- Strips
- Discs
- Glass ampoules
- Self-contained systems
- Spore suspensions
These indicators are regulated by ISO 11138 – Sterilization of health care products: Biological indicators and by pharmacopeias.
