Determination of the bioburden
In a typical case, the bioburden will be tested on all parts of the medical device intended for direct contact with the patient or with the drug. Depending on the requirements and the risk, the insides of the packaging or other parts of the product can also be tested.
As far as possible, the germs will be rinsed from the surface of the test body using a sterile rinsing liquid and will then be collected on a membrane filter. The membrane filter will then be inverted, placed on a culture medium and incubated in an incubator. After a sufficient incubation period, the number of germ-forming units will be evaluated.
Validation of the methods of analysis
The material and shape of the medical devices could be a decisive influence on whether any germs that are on the product are recovered.
In pilot trials with artificially contaminated example products, recovery assays should be performed to determine a correction factor so that routine analysis of the results can be evaluated correctly.
If increased values for the bioburden are determined in routine analysis, then the source of the contamination can eventually be found by performing a typification of the germs. A risk assessment can then be performed and additional measures can be implemented.