Hygiene and Microbiology

The research group & its main areas of research

The ‘Hygiene and Microbiology’ working group, headed by Prof. Dr Dirk Bockmühl, has laboratories with S2 safety classification. The focus is on research projects relating to hygiene in the non-clinical sector – in particular, the antimicrobial efficacy of consumer products (cleaning products, cosmetics) and their raw materials, as well as hygiene aspects of domestic appliances. Microbial counts are determined and antimicrobial products are tested in accordance with standards. The group is part of the European COMBAT consortium (funded by JPIAMR).

Analysis of microbial communities and their resistance

In the non-clinical setting, the research group analyses microbial communities – with a particular focus on microbial resistance and its spread. The findings are incorporated into test methods for assessing the antimicrobial efficacy of products and equipment; research is also conducted into the impact of hygiene measures on these communities and their potential for resistance.

Antibiotic resistance in the home

The domestic environment is an area that has so far been neglected in the context of antibiotic resistance – water-carrying systems such as drains, dishwashers and washing machines play an underestimated role. Funded by the German Federal Environmental Foundation (DBU, 2018–2022), potential pathways for the transfer of antibiotic resistance from the environment into the home were analysed and consumer recommendations were developed.

Development of practical efficacy tests

Standard methods often test antimicrobial products only against surrogate pathogens and reflect hospital rather than domestic conditions. The working group is developing bespoke, realistic methods – using different test organisms, long-term monitoring and realistic scenarios on a laboratory scale, including the consideration of appliances, cleaning products, contaminated surfaces and biofilms.

Laundry hygiene

Washing worn textiles is an important aspect of household hygiene. The working group investigates how the washing process removes microbial contamination and develops methods to assess the antimicrobial performance of washing processes in a realistic manner.

‘Certified Hygiene’ certificate

Rhein-Waal University of Applied Sciences awards the ‘Certified Hygiene’ seal to products and appliances with exceptional hygienic performance – such as washing machines and dishwashers. Verification is carried out through experimental tests based on standardised procedures, conducted exclusively by qualified staff at the university. The seal is of particular interest to manufacturers of domestic appliances, but can also be applied to fully automatic coffee machines or air purifiers.

Head: Prof. Dr Dirk Bockmühl · Tel. (02821) 806 73-208 · dirk.bockmuehl(at)hochschule-rhein-waal.de

Research staff:

Dr Nadine Merettig · Tel. (02821) 806 73-205
Ralf Lucassen, M.Sc. (Biotechnology Engineering) · Tel. (02821) 806 73-243
Marc-Kevin Zinn (PhD student) · Tel. (02821) 806 73-9786
Thomas Tewes (PhD student) · Tel. (02821) 806 73-9656

Alumni: Dr Britta Brands, Dr Laura Schages, Dr Jan Schages, Dr Marlitt Honisch.

A selection of the working group’s publications:

Ade C, Pum J, Abele I, Raggub L, Bockmühl D, Zöllner B (2021): Analysis of cycle threshold values in SARS-CoV-2 PCR in a long-term study. Journal of Clinical Virology.
Schages L, Lucassen R, Wichern F, Kalscheuer R, Bockmühl DP (2020): The household resistome – frequency of β-lactamases, class 1 integrons and antibiotic-resistant bacteria in the domestic environment and their reduction during automated dishwashing and laundry. Applied and Environmental Microbiology.
Zinn MK, Schages L, Bockmühl DP (2020): The Toothbrush Microbiome. Microorganisms.
Zinn MK, Bockmühl DP (2020): Did granny know best? Evaluating the antibacterial, antifungal and antiviral efficacy of acetic acid for home care procedures. BMC Microbiology.
Schages J, Stamminger R, Bockmühl DP (2020): A new method to evaluate the antimicrobial efficacy of domestic laundry detergents. Journal of Surfactants and Detergents.
Schages L, Wichern F, Kalscheuer R, Bockmühl DP (2020): Winter is coming – Impact of temperature on the variation of beta-lactamase and mcr genes in a wastewater treatment plant. Science of the Total Environment.
Brands B, Schulze Struchtrup S, Stamminger R, Bockmühl DP (2020): A method to evaluate factors influencing microbial reduction in domestic dishwashers. Journal of Applied Microbiology.
Bockmühl DP, Brands B, Lucassen R, Schages J, Zinn MK (2020): Realistic experimental approaches to evaluate hygiene-related effects in laundry and home care. Household and Personal Care Today.
Bockmühl DP, Schages J, Rehberg L (2019): Laundry and textile hygiene in healthcare and beyond. Microbial Cell.
Lucassen R, Rehberg L, Heyden M, Bockmühl D (2019): Strong correlation between the total phenotypic resistance of samples from household environments and the prevalence of class 1 integrons. PLoS ONE.
Schages J, Brands B, Heldt P, Kohlmann R, Pickel A, Bockmühl DP (2018): The influence of technical and microbiological parameters on the hygienic quality of coffee from fully automated coffee machines. Journal of Bioprocessing and Biotechniques.
Rehberg L, Frontzek A, Melhus A, Bockmühl DP (2017): Prevalence of β-lactamase genes in domestic washing machines and dishwashers and the impact of laundering processes on antibiotic-resistant bacteria. Journal of Applied Microbiology.
Bockmühl DP (2017): Laundry Hygiene – How to achieve more than just cleanliness? Journal of Applied Microbiology.
Dreßler I, Honisch M, Ziegler L, Budelmann H, Bockmühl DP (2016): Influence of material and surface properties on the persistence of Staphylococcus aureus on surfaces commonly found in hospitals. Hygiene and Medicine.
Brands B, Honisch M, Merettig N, Bichler S, Stamminger R, Kinnius J, Seifert M, Hardacker I, Kessler A, Weide M, Wrubbel N, Bockmühl DP (2016): Qualitative and quantitative analysis of microbial communities in household dishwashers in Germany. Tenside Surfactants Detergents.
Brands B, Honisch M, Wegner S, Bockmühl DP (2016): The effect of drying processes on the microbial load of laundry. Household and Personal Care Today.
Nix ID, Frontzek A, Bockmühl DP (2015): Characterisation of microbial communities in domestic washing machines. Tenside Surfactants Detergents.
Brands B, Bockmühl DP (2015): Experimental evaluation of hygienic conditions in domestic dishwashers. Tenside Surfactants Detergents.
Lucassen R, Blümke H, Born L, Fritz A, Geurtz P, Hoffmann N, Hoffmann L, Steiner R, Merettig N, Bockmühl DP (2014): The washing machine as a source of microbial contamination of domestic laundry – a case study. Household and Personal Care Today.
Eckert A, Booten Y, Jarchow M, Lucassen R, Nemitz L, Bockmühl DP (2014): Reduction of microorganisms by ironing. Household and Personal Care Today.
Honisch M, Stamminger R, Bockmühl DP (2014): Impact of time and temperature profiles in domestic washing machines on the inactivation of microorganisms. Journal of Applied Microbiology.
Lemm D, Merettig N, Lucassen R, Bockmühl DP (2014): Inactivation of human norovirus by common domestic laundry procedures. Tenside Surfactants Detergents.
Lucassen R, Merettig N, Bockmühl DP (2013): Antimicrobial efficacy of hygiene rinsers under consumer-related conditions. Tenside Surfactants Detergents.
Heinzel M, Kyas A, Weide MR, Breves R, Bockmühl DP (2010): Evaluation of the virucidal performance of domestic laundry procedures. International Journal of Hygiene and Environmental Health.