Research from the University of Helsinki Reveals How Wood Surface Treatments Influence Bacterial Communities and Indoor Hygiene

Research from the University of Helsinki Reveals How Wood Surface Treatments Influence Bacterial Communities and Indoor Hygiene

(IN BRIEF) A study conducted by researchers at the University of Helsinki has found that untreated wood surfaces support greater bacterial survival and diversity than treated wood surfaces. By examining bacterial adhesion, survival and transmission under both laboratory conditions and real-world environments, the research demonstrated that surface treatment significantly influences microbial communities on wood. Laboratory experiments focusing on Staphylococcus epidermidis and Pseudomonas aeruginosa showed that bacteria remained more viable on untreated wood, while treated surfaces reduced both bacterial quantity and species diversity. Field experiments confirmed that untreated surfaces hosted more diverse microbial communities. The findings suggest that material choices and surface treatments in buildings and furniture could influence indoor microbiota and hygiene. The research may eventually contribute to the development of new wood materials and surface treatments designed to promote healthier indoor environments or even beneficial microbial ecosystems.

(PRESS RELEASE) HELSINKI, 12-Mar-2026 — /EuropaWire/ — University of Helsinki researchers have published new findings indicating that bacteria tend to survive and persist more readily on untreated wood surfaces than on treated wood, offering new insights into how materials influence microbial activity in indoor environments. The study highlights how surface treatments can significantly affect bacterial adhesion, survival and the composition of microbial communities, with potential implications for hygiene management in homes, workplaces and public spaces.

The research examined how bacteria attach to, survive on and spread across both untreated and treated wood surfaces under controlled laboratory conditions and in real-world environments. By combining experimental laboratory work with field observations in public spaces, the study provided a broader understanding of how wood materials interact with microbial communities in everyday settings.

In laboratory experiments, scientists focused on two types of bacteria: Staphylococcus epidermidis, which naturally occurs on human skin and is generally harmless, and Pseudomonas aeruginosa, a bacterium capable of causing infections and known for its resilience in challenging environments. These two species were selected to represent both typical skin-associated microbes and bacteria that may pose health risks in certain circumstances.

The results showed that untreated wood surfaces supported a greater number of bacteria and allowed them to remain viable for longer periods compared with treated wood surfaces. Surface treatments appeared to reduce both the quantity and diversity of bacteria present on the material.

Doctoral researcher Elina Kettunen explained that treating wood surfaces influenced the microbiota that forms on them. According to the findings, treated wood contained fewer bacterial cells and fewer species, demonstrating that surface treatment plays a significant role in shaping microbial communities. Untreated wood, however, may help maintain a wider range of microbes, including potentially beneficial ones.

The research also demonstrated the value of combining laboratory studies with field-based observations. While laboratory experiments enabled scientists to closely monitor bacterial behaviour under controlled conditions, field tests in public environments revealed how these processes occur within naturally occurring microbial communities.

For example, the bacterium S. epidermidis survived better on untreated wood during laboratory testing. Field studies also revealed that untreated wood surfaces hosted a more diverse and viable bacterial population. These findings suggest that the natural characteristics of wood can influence microbial ecosystems, although environmental conditions and interactions between microbial species can modify these effects.

The study further suggests that material choices in buildings and interior spaces may influence the microbial environment within those spaces. Although the laboratory portion of the research examined only two bacterial species and a limited number of materials, the findings offer valuable initial evidence that material selection can shape microbial communities that develop on surfaces.

According to Tuula Jyske, Associate Professor of Wood Material Science at the University of Helsinki, factors such as indoor environmental health, durability of materials and microbial management are key considerations in construction and interior design. Understanding how different materials and surface treatments influence microbiota could help guide future design decisions.

These insights could be particularly relevant in environments where hygiene and surface cleanliness are important, such as furniture surfaces, interior wall materials and other frequently touched areas. Over time, the research may contribute to the development of wood materials and surface treatments designed to support healthier indoor environments, including surfaces that encourage beneficial microbial communities.

The study, titled From antimicrobial activity to microbial ecology: Untreated and treated wood surfaces shape bacterial survival and community diversity in indoor environments, was authored by Elina Kettunen, Julia Ahlblad, Mika Kurkilahti, Pekka Varmanen, Kirsi Savijoki and Tuula Jyske and published in the journal Journal of Hazardous Materials Advances, Volume 22, 2026, 101090, ISSN 2772-4166, https://doi.org/10.1016/j.hazadv.2026.101090

Media Contacts:

Tuula Jyske
Associate Professor
Department of Forest Sciences
tuula.jyske@helsinki.fi
+358294158174

Elina Kettunen
Doctoral Researcher
Department of Forest Sciences
elina.h.kettunen@helsinki.fi
+358294158212

SOURCE: University of Helsinki