Dr. Lehmann GmbH & Co. KG

Preservation challenge test

The central element for evaluating the biological stability of chemical-technical products is the preservative loading test (KBT). Here, in principle, a product is inoculated with germs and then observed the further development of the germs by microbiological methods, the aim of which is their complete reduction. Numerous methods exist for performing such tests, including parameters such as inoculated germ species, added germ count, frequency of inoculation (s), germ count times, storage temperatures during the test, and the like. differ.

The standard tests for chemical-technical and cosmetic products have been established as a single-use procedure based on the methodology (Pharm.Eur.-method) described in the various pharmacopoeias as well as a repetitive loading procedure. Both methods are available - even in modified versions. It is necessary to agree on the respective product and its field of application in order to assess with which method a safe, practical assessment can be achieved. In addition, it may be important to include problematic germs (e.g., "housekeeping") in the trials to safely capture the microbial contamination risk actually present under production or operating conditions.

Ongoing investigations are kept under constant control. In the case of emerging microbiological instabilities, we contact the client to discuss possibilities for improvement in a timely manner. Canceled checks are calculated at a reduced cost rate.