Bioburden describes the total microbial count of a surface. The purpose of bioburden identification is to ascertain the population of viable microorganisms’ bacteria and fungi on or in a product or its packaging. The determination of the number is a significant step in the validation of a sterilization procedure and in process-related quality evaluations when cleaning or manufacturing a health item. For this purpose, the item is placed in a culture medium, or it is rinsed in a sterile solution, the rinsing medium is filet-red through a sterile membrane and the membrane is applied to a number of culture media. The culture media are incubated for many days and the microorganism colonies formed in the procedure are counted. The number of colonies increased is then equivalent to the number of colony-forming units CFUs, individual germs or groups of microorganisms adhering to each other that were initially on the item.
By using various culture media and incubation conditions, it is initially possible to roughly distinguish between bacteria and fungi. By employing additional specific media, a further specification of the germs found can then be carried out primarily for the bacteria. This can then be used to localize the source of contamination during the production and/or cleaning procedure for the goods. The material and the geometry of a health product have a significant influence on the efficacy of the test approach. Thus, a one-time validation of this test method ought to be carried out for each item. For this purpose, the item is inoculated with a known number of a known test organism and then analysed with clearly defined parameters. At the conclusion of the evaluation, the CFUs discovered are counted and compared with the amount applied.
This ratio is the recovery rate. This is then utilized to compute a correction factor that is calculated into all then conducted bioburden testing determinations on this item. In compliance with the DIN EN ISO 11737-1standard, the recovery rate should be at least 50%, otherwise the parameters of this test method has to be changed and tested again. If the recovery rate has reached a decent price, all bioburden determinations on this item has to be carried out with precisely the same parameters as during validation.