Annual Conference 2025 of the Association for General and Applied Microbiology - Jahrestagung 2025 der Vereinigung für Allgemeine und Angewandte Mikrobiologie

Chair

Prof. Dr.

Antimicrobial efficacy and application of disinfectants

FG Quality management

In clinical set-ups as well as in the production environment, e.g. in pharmaceutical or food production, hygiene is of outmost importansce.When confronted with pathogens or spoilage agents, especially if they are not yet well studied, effective hygiene protocols are needed. In the medical field, effective preventive measures are key to prevent vulnerable patients from infections. In production areas, effective hygiene measures are needed to protect goods from spoilage or microbial contamination.The broad portfolio of standards/laboratory tests, to substantiate activity claims for chemical disinfectants addressing the special features of applications of antimicrobial formulations will be explained. Furthermore, the concept of using standardized surrogate test organisms is illustrated, and the European standardized test approach to claim microbicidal and virucidal efficacy, the specificity of claims and their relevance for hygiene measures are introduced.

Invited lecture

Pulsed Light: An important advance in Pre-fill Sanitization

Safety is important in all food industries, and that"s especially true in the dairy business. Yogurt, as example, is highly susceptible to contamination by microorganisms that can come from various sources, including the equipment used in production. This makes pre-fill sanitization of yogurt cups a crucial step in a safe production process. It eliminates potential contaminants in the yogurt cup right before filling, ensuring that the yogurt remains safe for consumption and complies with safety standards.The talk will shed light on the sanitization of surfaces using pulsed Xenon light. It will illuminate the advantages and discuss some limitations.

Plasma sterilization of thermolabile materials

The motivation for new sterilization methods is based on the treatment of thermolabile materials like food packing materials, specific implant materials like UHMWPE, pharmaceutical tubs for syringe packing and much more. Autoclaving is not always possible, due to heat limitations or time restrictions. Ethylene oxide is toxic, mutagenic and carcinogenic, furthermore it is even explosive. Beside the fact that there is a large variety of different methods, there is no one which is well suited for a fast and reliable treatment of heat sensitive materials. This talk will show that low pressure plasma sterilization offers a well investigated and understood method that is able to exactly fulfill the above mentioned restrictions: it is fast, cold, and its mechanisms are quantified. As test samples, B. subtilis spores are investigated. Contamination procedure has been standardized, a defined monolayer on sample carrier is realized by an in-house made spray coater. The plasma system used for all spore treatments is based on an inductively coupled rf-plasma reactor with large volume. Typically filled with a mixture of argon, nitrogen and oxygen and operated at 5 Pa, the plasma itself is carefully and quantitatively characterized. Thereby delivering its fundamental parameters like the gas temperature, the electron density, electron energy distribution function (EEDF) an many others. Most importantly, the light emission in the VUV/UV range (116-280 nm), is determined absolutely and relatively calibrated. In this wavelength region absorption of the spore DNA is largest. It is shown that an inactivation of spores is strongly based on the gas mixture filled in the plasma chamber. The reason for this behavior strongly relates on the individual excited levels of each atom or molecule thereby emitting at different wavelengths with different intensities. Further on, the inactivation is correlated to a well-known wavelength dependent formula from Munakata et al (Photochem. Photobiol. 54 (1991)). Finally, plasma etching of spores is measured and the ICP sterilization is shown for an industrial system for pharmaceutical filling of syringes.

FG Quality management

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