How contaminated are our countertops?
Written by Theint Aung
Edited by Aaron Wright
Jan 23rd 2022
Edited by Aaron Wright
Jan 23rd 2022
With the advent of the COVID-19 pandemic, we have all become more conscious of the microbes in our environment. We have wiped down countertops more than ever with the purpose of protecting ourselves from different bacteria and viruses. But how much of these indoor pollutants are deposited on surfaces? And how effective is it to clean them?
A group of scientists had already studied in 2015 that the properties of the surfaces can affect the deposition of the bioaerosols–microorganisms dispersed in the air–in laboratories (Tamburini et al., 2015). Researchers placed samples of six different surface materials, glass (G), stainless steel AISI 304 (INOX), fine porcelain stoneware (LG), post-forming laminate (PFL), high-performing laminate (HPL), and enamel steel (S), in a laboratory and allowed daily routine, such as microbial analyses and opening windows, to be carried out as usual. After 30 days, samples were taken from the surfaces, cultured, and analyzed.
All microbial groups were observed with a slightly different contamination composition and final cell concentration among the surfaces. The PFL and HPL had the highest microbial contamination, followed in decreasing order by the glass, then enamel, and stainless steel. Finally, the fine porcelain stoneware exhibited the lowest microbial contamination. In general, fungi were the dominant categorization of microbes on surfaces, with >60% of TMC (Total Microbial Count) on all surfaces except glass. Bacterial groups (psychrophilic, mesophilic, and staphylococci) were equally distributing the remaining 40% of TMC.
They had also found out that cleaning the surfaces with a detergent solution reduced TMC by more than 99%. However, 7 days after cleaning, the surfaces were as contaminated as they were before the cleaning. So, it would be wise to disinfect the surfaces at least every week!
Surfaces can provide favorable environments for the growth and metabolism of various microbes, therefore it is crucial to clean them regularly to reduce the number of germs and the risk of infection.
References
Tamburini, E., Donegà, V., Marchetti, M. G., Pedrini, P., Monticelli, C., & Balbo, A. (2015). Study on Microbial Deposition and Contamination onto Six Surfaces Commonly Used in Chemical and Microbiological Laboratories. International journal of environmental research and public health, 12(7), 8295–8311. https://doi.org/10.3390/ijerph120708295
Image by Theint Aung