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Product Bioburden – Tissue

The Bioburden test for tissue determines the total number of viable microorganisms in or on a tissue product or solution. It is performed on any tissue product that requires control and/or monitoring of bioburden counts, usually as part of a sterilization program. This test acts as an early warning system for possible production problems that could lead to inadequate sterilization or disinfection processing. It is also used to calculate the necessary dose for effective radiation sterilization and to monitor product routinely as part of quarterly dose audits.

Find additional information on coordinated Quarterly Dose Audits (QDAs) and Radiation Sterilization.

Nelson Labs performs this test in accordance with ANSI/AAMI/ISO 11737-1 and is most commonly referenced in the Radiation Sterilization standards (ANSI/AAMI/ISO 11137-1 & 2) and the EO Sterilization standard (ANSI/AAMI/ISO 11135).

Applicable Standards

    • ANSI/AAMI/ISO 11737
    • ANSI/AAMI/ISO 11137
    • ISO 11135
    • EN 1174
    • EN 13795

Testing Locations

  • Salt Lake City, UT, USA
  • Itasca, IL, USA
  • Ontario, CA, USA
  • Esperaerde, Denmark
  • Leuven, Belgium
  • Petit-Rechain, Belgium
  • Somercotes, England
  • Rantigny, France
  • Wiesbaden, Germany
  • Shanghai, China

Learn more about our locations and their certifications.

Study Outline

Routine testing of tissue should be performed to demonstrate that the tissue processing remains in control. The appropriate frequency and number of samples depend upon the sterility assurance level (SAL), type of product, type of sterilization used, environmental control, and the process controls of the manufacturer or tissue processor.

In order to validate a bioburden test, a recovery efficiency needs to be performed. There are essentially two approaches available: repetitive treatment (also referred to as exhaustive recovery) or product inoculation. Ideally, a recovery efficiency should be established prior to the start of any bioburden test. It should be performed on a minimum of three samples. The recovery efficiency is then validated and can be applied to all future testing of that product. Due to the inhibitory nature of tissue samples, this can prove challenging at times and an initial consult with technical lab staff is recommended.

The AAMI Radiation Sterilization guideline (ANSI/AAMI/ISO 11137) tissue sample requirements for bioburden with each quarterly dose audit. Monthly bioburden testing may be required depending on the validated sterilization dose.

Bioburden tests may include aerobic bacteria, spores, aerobic fungi (yeasts and molds), and anaerobes. Many factors enter into the choice of the type of tests most appropriate for your product. Generally, one should test for aerobic bacteria and fungi.

For tissue products with low bioburden, the Most Probable Number (MPN) test may be utilized. This testing involves immersing the product directly in nutritive media and following a seven-day incubation, scoring the media for growth or no growth.

If you have additional questions about Bioburden Tissue testing, or would like to consult with the experts at Nelson Labs, just send us a request or call us at +1 (801) 290-7500.