Abt. Allgemeine Hygiene und Umweltmedizin

Test Unit for Stability Testing Which Confirms the Microbial Integrity of Medical Sterile Packaging Systems

We offer a procedure (test unit) for the assessment of continuing sterility throughout the transport as well as shelf life of terminally sterilized wrapped medical devices.
Detailed description:
The most important function of medical sterile packaging systems is to maintain the sterility of the wrapped product unchanged during transport and storage. Since the packaging must also ensure entry of the sterilizing agent (e.g. superheated and saturated steam, ethylene oxide), the packaging concerned possesses porous component fractions that are permeable to gases or consist entirely of such materials. The packaging therefore acts like a filter in that it allows the gaseous sterilizing agent and the air to pass through, but should prevent microorganisms from penetrating the packaging. Factors affecting sterility are: quality of wrapper material, storage conditions, atmospheric pressure changes during transport, airborne microbial count, and temperature changes.
We developed a test which demonstrates the sterility of a wrapped product through its shelf life.
The test kits consist of a nutrient board and a frangible glass ampoule filled with water. The nutrient board is placed on a thermoresistant petri dish. The ampoule is placed within the interior cavity of a thermoresistant cylindrical plastic tube whose one end is closed, the other one is open. The open end is provided with a glass pipette. This end of the tube is placed over the petri dishes with the nutrient board. The plastic tube around the ampoule serves to ensure that when the glass ampoule is crushed in order to humidify the nutrient board via the tube to activate the culture, pieces of glass are captured and can not destroy the packaging. The test kit is placed in heat sealable pouches of paper and plastic film construction and sterilized in the same way as the medical devices. After typical storage of the sterilized wrapped medical device, the stability-indicating test is performed by fracturing the frangible glass ampoule without damaging the package. We use a clamp for shattering the frangible glass ampoule. The water is brought into contact with the nutrient board via the pipette by pressing the ampoule so that the board is humidified. The packaging with the test kit is then subjected to an incubation process for 48 hours. After incubation, the packaging is opened and the nutrient board is checked for microbial growth. If no microbial growth is observed, the test confirms the continued sterility during the product’s transport and shelf life.
Innovative aspect:
Sterility is a stability characteristic which should be confirmed by a final testing, when, after the period of transport and storage, the wrapped sterile devices are used. We developed a new test, which can demonstrate the microbial integrity of safe storage times for terminally sterilized wrapped medical products currently used in hospitals.
Main advantages:
Instead of the products to be sterilized, the testing unit can be inserted into the sterilization packaging. After typical storage of the sterilized wrapped products the test could then be carried out, wherein the result of the test can be applied to the entire batch of sterilized items.