What is a Bioburden Test, and Why is it Important?
Bioburden is a term used to describe the sum of viable microorganisms on or within a product. It is used in multiple situations pertaining to sterilization and quality control: validation/requalification of sterilization processes and assessment of a cleaning process’ efficiency are just two examples.
In terms of sterility assurance, bioburden is the value that is used to determine the dose of radiation (gamma or e-beam) that is required to achieve a sterility assurance level (SAL) of 10-6. A SAL of this value is standard in the industry and is the minimum requirement for a sterilization process to achieve.
One aspect of bioburden that is important to keep in mind is that it can fluctuate between different batches/lots of product due to the variability of microbial exposure sources. Therefore, bioburden evaluations are generally conducted as campaigns spanning multiple lots or batches with multiple samples per batch.
What is the ISO 11737 Bioburden Test?
The ISO 11737 bioburden test is a procedure used to remove and quantify viable microorganisms from a product. It considers method suitability, potential microorganism types and their locations on a product, the effect of the method on microorganism viability and the nature of the product being tested. This test is required in product submissions to document the bioburden value and how well a sterilization process will work on the product. Requirements for testing are found in ISO 11737-1:2018 “Sterilization of health care products – Microbiological methods – Part 1: Determination of a population of microorganisms on products”.
The method of bioburden testing is highly dependent on the material of the product. For example, if the item its completely solid we would completely immerse it into a liquid (e.g., PBS) and sonicate it, followed by membrane filtration and plating. The plates would be incubated and eventually counted to determine the bioburden.
The ISO 11737 Bioburden Test is Fast, Inexpensive, and Reliable
Bioburden tests are quick, inexpensive, and reliable means of characterizing the microbial load of a medical device or other object. To explore bioburden testing options, contact Microchem Laboratory today.
Sources:
The International Organization for Standardization. (n.d.). ISO 11737-1:2018(E) Sterilization of health care products – Microbiological methods – Part 1: Determination of a population of microorganisms on products. https://www.iso.org/obp/ui/#iso:std:iso:11737:-1:ed-3:v1:en
Millipore Sigma. (n.d.) Bioburden Testing. https://www.sigmaaldrich.com/US/en/applications/microbiological-testing/bioburden-testing
Kowalski, J.B., Mosley, G. (2011, March 29). Estimation of Average Bioburden Values for Low-Bioburden Products. Medical Device and Diagnostic Industry. https://www.mddionline.com/sterilization/estimation-of-average-bioburden-values-for-low-bioburden-products
Bailey, M. (2010, March). Notes on bioburden distribution metrics: The log-normal distribution. The Irradiation Panel. Digital Download.
