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Biological Indicators (BI)

Biological Indicators (BI) are generally accepted as the most suitable device to use for monitoring sterilization processes in Steam, Ethylene Oxide & Dry Heat, Gamma / E-beam, and H₂O₂ / Plasma. The BI contain a specific microorganism considered to be most resistant to the specific type of sterilization process. A BI is to be included with the products for every sterilization cycle. If the organism in the BI is successfully killed, then the product is expected to be sterile as well. The BI can be used to monitor the sterilization of equipment, materials, and packaging components

The indicators can be supplied as:

  • Spore Strips 

  • Spore Suspensions

  • Self-contained Vials

BI are conventional spore growth readout indicators specifically designed for reliable monitoring of sterilization processes without the use of enzyme-based technology or specific monitoring devices. All BI comply with the performance requirements of ANSI / AAMI / ISO 11138-1 and the USP requirements. Incubation time depends on the types of BI:

  • Strips need to be incubated 7 days

  • Self-contained BI, 24/48 hour

  • For steam, a rapid 10-hour indicator is available


Spore Strips

Biological spore strip indicators consist of bacterial spores impregnated onto a paper filter carrier contained within a glassine envelope. For usage, after the sterilization cycle, the spore strip is removed from the load and aseptically transferred into appropriate microbiological broth medium. A viable microorganism, when transferred to standard broth, will demonstrate growth showing noticeable turbidity. Turbidity indicates a sterilization process failure, and a clear broth indicates a successful sterilization cycle.


Spore Suspensions


Spore suspensions are biological indicators used for direct inoculating on or into units of the product to be sterilized, or other surfaces such as a disc to act as a BI.

Spore suspensions are available for sterilization processes using:

  • Steam

  • Ethylene Oxide

  • Dry Heat

  • Gamma / E-beam

Spore suspensions are provided with population and resistance values to the sterilization process.


Each vial contains 10 ml of spore suspension in 20% ethanol or in an aqueous medium.



Self-contained biological indicators are fast-working, reliable indicators for monitoring sterilization processes using: 

  • Steam, 

  • H₂O₂ / Plasma 

  • Ethylene Oxide & Dry heat

These indicators consist of a self-contained unit that includes bacterial spores impregnated onto a paper strip, and a small glass ampoule containing a proprietary formulation of soybean casein digest culture media with a pH indicator. The strip and the glass ampoule are encased in a plastic vial that serves as the culture tube. After the sterilization cycle, the plastic vial is incubated under described conditions. The pH indicator remains purple when there is no spore growth and turns yellow when there is spore growth. This allows quick visual determination of sterilization success or failures (yellow color).

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