What is a Biological Indicator?

Biological indicators are used to validate sterilization processes in different industries.

They are indicators that determine the lethality of sterile processing indicating, that is, they indicate whether a material subjected to a sterilization process is completely free of living microorganisms.

In general, a biological indicator is composed of a population of spores of bacteria highly resistant to the sterilization method used.

How does a Biological Indicator work?

When the sterilization process is finished, the biological indicator is used to determine if there are still viable spores in it. If there are surviving spores, the sterilization process is ruled out. If no surviving spores are detected, the sterilization process is validated.

To analyze whether spores survived after sterilization, the biological indicators are incubated. Incubation results are analyzed according to the type of indicator used.

In the case of fluorescence indicators, the detection of fluorescence signal is the evidence of survival of the microorganism to the sterilization process. In the case of conventional indicators, if the culture medium in the indicator changes color or turbidity is observed, spore growth is confirmed and the sterilization process is considered unsuccessful, on the other hand, if there is no fluorescence signal or changes in the appearance of the culture medium is validated by the sterilization process.

Types of biological indicators

Due to the high quality standards in the pharmaceutical, food and health industries, there must be a strict control for the sterilization processes that have been carried out properly and it can be assured that the material to be sterilized is really sterile after having it. exposed to some sterilization process. There are many methods to sterilize and for each method there is a specific biological indicator to validate the process.

STEAM

VH2O2

DRY

FORM

Spore strips

Inoculated strip carrier with a population of spores recommended for validation and monitoring of sterilization processes

Ampoules

Glass ampoule containing the recommended spore population dispersed in a culture

Self-Conteined
Biological Indicators

Medium specially designed to monitor liquid sterilization processes

Spore strips

Biological indicator contains in the same presentation (plastic tube) the recommended spore population and the culture medium needed to reveal its result.

Types of biological indicators

STEAM

VH2O2

DRY

FORM

Spore Strips

Inoculated strip carrier with a population of spores recommended for validation and monitoring of sterilization processes

Ampoules

Glass ampoule containing the recommended spore population dispersed in a culture

Self-Contained
Biological Indicators

Medium specially designed to monitor liquid sterilization processes

Spore strips

Biological indicator contains in the same presentation (plastic tube) the recommended spore population and the culture medium needed to reveal its result.