When we talk about bioburden, we’re talking about the number of bacterial or fungal cells that live on an unsterilised surface. We measure this in terms of colony-forming units (CFU), and a CFU is an estimate of the number of viable organisms found on a sample.
Read our full guide to what bioburden is, and why it matters.
Bioburden Limits for Medical Devices
Most medical devices will have a bioburden between 0 and 150 CFUs.
What Types of Devices Have a Higher Bioburden?
Medical devices with large, flat surfaces will usually have a higher bioburden than smaller devices, as they provide a larger surface area on which microorganisms can live. Also, microorganisms can live for longer on hard surfaces like plastic and metal, than on porous surfaces like fabric.
Beyond the size and complexity of the device, and the material it’s made from, a device’s actual bioburden will depend on how it was made. The manufacturing process can make a huge difference, including the environmental conditions in which it was made, and the amount of handling that took place during its assembly.
Bioburden Testing of Medical Devices
Bioburden testing will detect the presence of a number of microorganisms, including:
- Aerobic bacteria
- Aerobic fungi, such as yeasts and moulds
Hospitals and other healthcare settings will sterilise all medical devices according to the manufacturers’ recommendations as a standard infection control precaution.
So hospitals and healthcare settings won’t usually do their own bioburden testing. Rather, most testing is done during the manufacturing process.
What’s a Reasonable Bioburden Limit for Medical Devices?
When purchasing medical equipment, it’s a good idea to choose medical devices with low bioburdens. The CFU count should be as low to zero as possible. You may wish to avoid purchasing any equipment with a CFU in excess of 100, though sometimes this may not be possible.
Some standards may specify the maximum CFU for medical devices in some settings. The higher a device’s bioburden, the harder it will be to sterilise. And some sterilisation processes can release harmful endotoxins.
So using devices with low CFUs limits the chances of contamination. It can also make your operations more efficient, as your sterilisation processes will be relatively straightforward, and considerably safer. And if a medical device has a low CFU, practitioners will find it much easier to remove any contaminants left over from the manufacturing process before use.
Bioburdens Are A Product of The Manufacturing Process
Regular bioburden testing allows medical device manufacturers to ensure that their manufacturing processes are as safe as possible. If bioburden testing returns high CFUs, then device manufacturers can introduce tighter measures to control contamination in their clean rooms:
- Use high quality air purifiers to remove harmful contaminants from the air.
- Implement thorough cleaning routines, effective PPE use, and other standard infection control precautions.
- Regularly test all production areas for both surface and air particles to measure the effectiveness of the bioburden control measures.
Expert Cleanroom Testing and Monitoring Services
At Cairn Technology, we offer comprehensive cleanroom testing and monitoring services.
Our services include:
- Active and passive bioburden sampling.
- Airborne particulate sampling.
- Instrument and hard-surface bioburden sampling.
- Endotoxin testing of washed instruments, sterile instruments, and reverse osmosis (RO) water.
- Air pressure differential testing – to ensure that your air purification systems are working as effectively as possible.
Learn more about our sterile services cleanroom testing and monitoring services.