Cooking-Derived Organic Compounds Shape Bacterial Communities on Household Surfaces

Understanding the factors influencing chemical and biological constituent accumulation on indoor surfaces is crucial, especially as individuals spend approximately 90% of their time indoors and frequently interact with these surfaces. However, the temporal relationships between these constituents remain unclear, as most field studies have relied on single-time snapshots and seldom examined the interplay between chemical and biological dynamics. We conducted a month-long spatiotemporal field study across 20 households in Hong Kong to investigate the factors influencing chemical and biological constituents on common indoor surfaces. Among the 16 household- and occupant-related factors analyzed, routine oil-based cooking was the primary driver of microbial diversity and composition on indoor surfaces. Surfaces in kitchens with frequent cooking exhibited elevated total organic carbon levels, which were linked to an increased bacterial abundance. A focused analysis of six kitchens with well-controlled frequencies of oil-based cooking revealed that cooking-derived organic compounds, particularly alkanes, promoted bacterial abundance while reducing microbial diversity. Network analysis further revealed strong interactions between these organic compounds and bacterial taxa, especially those within the Proteobacteria and Firmicutes phyla. These findings highlight the impact of routine household activities on indoor chemical-biological interactions, enhancing our understanding and informing strategies to improve indoor environments and occupant well-being.