Evaluating good things on bioburden testing

Bioburden testing is an essential component of microbiological monitoring programmes when manufacturing sterile medical devices. Tracy Dennison, High Edge Consulting, looks at why testing is necessary for medical devices which are to be sterilised. The Results of bioburden testing supply producers with a ‘snapshot’ in time but the issue is that the situation could change without warning. A manufacturer could be shown a bioburden result that neglects the action limit apparently for no apparent reason. Because of the nature of microbiological testing, the bioburden effect might be discovered only after the medical device has been sterilised. So just what are the consequences for the maker of a failed medical apparatus bioburden result, given that many sterilisation methods are confirmed on an overkill approach, using a high degree of conservativeness built in.

Bioburden Testing determines the microbiological loading of a medical device that is a combination of the microbial content of raw materials, storage requirements, manufacturing surroundings and cleanliness, production process steps and employees. So long as the bioburden result stays consistent and within defined limits, it suggests there is been no change in any aspect that could result in increased microbial contamination, particularly as the bioburden signifies the microbial barrier to the sterilisation procedure. To comply with the standard, ISO 13485 Medical devices — Quality management systems Requirements for regulatory purposes, all non-conformances have to be researched, and this includes bioburden outcomes. If the matter is serious enough or continual bioburden trips are mentioned, this may require converting to a CAPA Corrective Action and Preventive Action.

Investigating Bioburden trips for medical devices can be problematic as the matter is reactive in nature, in an event that has already happened. Root cause analysis is determined by the usage of excellent problem solving instruments for instance, the Ishikawa or fishbone diagram in Figure 1 with a few suggested topic areas using a multidisciplinary team. The point is to try to determine if there was a step change in the process that has resulted in the bioburden testing excursion. The investigation will most likely need additional testing at incoming merchandise and all phases of manufacture and this is usually time consuming and expensive. Previous hazard analysis should have identified typical sources of microbial contamination which need control; even a small change in a procedure could have a large microbial effect.