Performed according to ISO 11137-1, the bioburden test must be evaluated for each medical device before proceeding with the actual (routine) bioburden testing itself. The purpose of this study is to ensure that the method employed is effective in recovering microorganisms present on the product and growth of the recovered microorganisms is not hindered. The validation process is important to avoid inadequate sterilization due to underestimation of the product’s true bioburden.
There are typically two phases to a complete bioburden validation. First the recovery validation comprising of either the inoculative or repetitive recovery method, will determine whether a correction factor should be applied to the routine bioburden test. Secondly, a screening study may be conducted to determine whether the test sample’s natural bioburden is inhibited, damaged or killed by released substances from the product itself during the extraction process.
| Test Code | Description | Sample requirements |
| BIO-I | Bioburden Validation - Inoculation recovery method - Known amount of spores are inoculate onto a sterile device and the percent recovery |
Sterile samples are required |
| BIO-R | Bioburden Validation - Repetitive recovery method (5 total extractions) - Exhaustive extractions are performed on the product to determine the percent recovery. |
Non-sterile samples are required. (Not recommended for products with very low bioburden counts) |
| BIO-S | Screening study - Conducted in presence of material with bacteriostatic / fungistatic activity - In cases where consistently low recoveries are obtained |
Sterile samples are required |