Biological indicators


The biological indicators, provided by SAFE Sterilization ApS, are designed for control and validation of sterilization processes.

Moist heat sterilization (autoclaving) is carried out by use of dry saturated steam under pressure. In order to kill microorganisms, including bacterial spores, a temperature of at least 121°C is required for 15 minutes or 134°C for 3 minutes or equivalent combination of temperature and time, to achieve the specified kill effect.

Sterilization with dry heat (dry heat sterilisation) takes place in a dry sterilizer requiring effective circulation of the hot air. It requires higher temperature and longer time to dry heat sterilize than to sterilize in an autoclave. This is due to dry air has significantly lower heat capacity and a poorer thermal conductivity than dry saturated steam as in an autoclave.

Killing off microorganisms, including bacterial spores, is achieved in dry sterilisation by a minimum requirement of temperature against cycle time: 160°C for 2 hours, 170°C for 1 hour, or 180°C for 30 minutes, or equivalent combination in order to achieve the specified kill effect. It is important to measure the sterilization time from the moment the specified temperature is achieved in the autoclave/dry sterilizer.

Product description

The biological indicators have been manufactured in accordance with DS/EN ISO 11138-1, 11138-3 and DS/EN ISO 11138-4. SAFE Sterilization has selected a combined indicator to be used for sterilization with steam as well as dry heat.

The bacterial spores come from strains of standardized microorganisms from, for example, ATTC (American Type Culture Collection) or NRRL (ARS Culture Collection).

The biological indicators used to test steam sterilisation (autoclaves) are with bacterial spores from Geobacillus stearothermophilus,and to test dry heat (dry sterilizers), bacterial spores from Bacillus atrophaeus.These bacterial spores have high resistance (D-value) to the specific sterilization method and are therefore suitable for periodic monitoring and validating of these sterilization processes.


Biological indicators are used for periodic verification of sterilization processes

The biological indicators are also used for validations, post-repair verification, as well as for verifying sterilization processes of temporary equipment.

Testinterval for brug af biologiske indikatorer er angivet i branchestandarder, Nationale Infektionshygiejniske Retningslinjer (NIR), samt som guidelines hos brancheorganisationer.

Please refer to our User guide and Recommendations for the healthcare sector on our website, Danish industry only.


Always use a validated autoclave or dry sterilizer for sterilization of equipment.

Storage, durability and disposal

Biological indicators should be stored at 2-24°C, dry and protected from direct sunlight.

Expiration date is indicated on the biological indicator. Never use an expired biological indicator.

Unused biological indicators must be sterilized and can be discarded as ordinary waste. If the biological indicators are not sterilized, you must dispose of them as clinical hazardous waste.


SafeSterilization offers subscription plans, contact us for more information.

Biological indicators are also sold individually, e.g. for the validation of equipment, additional checks after repairing the sterilizer or when using a loan sterilizer. Contact Safe to learn more.

We use a product from

Steris Corp

5960 Heisley Road
Mentor. OH 44060-1838