Bioburden Testing: Everything You Need to Know
What is Bioburden Testing?
The word bioburden comes from ‘bio’ meaning life, and ‘burden’ meaning presence or load. Therefore, bioburden refers to the amount of living organisms – like bacteria or fungi- naturally present on a device.
Bioburden testing is the process of determining the total number of viable microorganisms (Total Viable Count) present in or on a medical device. This testing is crucial for medical device manufacturers in ensuring a high level of cleanliness on their sterile or non-sterile devices. This is also a key requirement of the ISO 11737-1:2018 + A1: 2021 standard that medical manufacturers must comply to.
What causes a high bioburden count?
A high bioburden count is primarily caused by contamination introduced during the various phases of manufacturing a medical device. Sources of contamination can come from personnel handling, environmental exposure, or even the water used in production. Due to the number of variables involved in any manufacturing process, routine bioburden monitoring is recommended, even if bioburden contamination is considered a low risk.
How is Bioburden Testing performed?
There are several key requirements for Bioburden determination on medical devices:
- Suitability analysis – this preliminary test validates the test method and screens for any substances on the device or introduced during recovery that may affect bioburden measurement. If interference is detected, a neutralization step is implemented to ensure accurate results.
- Selection of samples – using a complete product is always the preferred option. However, alternative approaches include pooling multiple products into a single sample or testing representative portions separately.
- Selection of the most effective recovery method – the common methods being swabbing, flushing or ultrasonication.
- Total Viable Count (TVC) measurements – the recovered microorganisms are quantified by either directly plating out aliquots of the recovered liquid after the recovery method or filtering the entire recovery liquid. We’ve written everything you need to know about TVC in the prior post.
In short, after the chosen method has been validated during the suitability analysis, the selected device(s) undergo a recovery method and TVC measurements are performed using the chosen method.
Bioburden Analysis – Key Considerations
When selecting a device for bioburden analysis, it is important to choose a device that best represents the manufacturing process, including packaging, routine production and materials.
Since the analysis only validates the bioburden of the specific product and its specific manufacturing conditions, an expiry date for the bioburden result will be established, due to the high probability of manufacturing conditions changing with time.
It may not be possible to evaluate an entire device, hence it is equally vital to choose sample portions which are representative of a whole device, particularly parts of the device which present the greatest microbiological challenge.
If the medical device is intended to be sterile, then bioburden testing helps validating the devices compliance with sterilisation requirements. However, if the device is intended to be non-sterile, then bioburden testing should meet the predefined cleanliness limits. Further analysis for validating sterilisation is through the EN ISO 17665-1:2006 Sterilisation Validation standard. This testing involves inoculating devices with a biological challenge, subjecting them to the sterilisation cycle, and then assessing whether any of the challenge microorganism remains.
Regulatory requirements can be complex, but ensuring product cleanliness and safety is critical. Test Labs can support you in achieving compliance with bioburden and sterilization standards. Contact us to learn how we can help streamline your testing process and meet industry regulations.
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