The researchers also examined whether certain lifestyle habits such as gargling, consumption of natto, and use of the different modes of transportation—public transportation, personal vehicle, and walking or biking— had any effect on the microbial counts on the masks.
“We found no differences in the bacterial or fungal colony counts on both sides of the masks among the three transportation systems,” the authors wrote.
There were also no differences in microbial counts on masks of participants who gargled once a day. Gargling is a Japanese custom believed to prevent respiratory infections. The practice is often recommended by the Japanese health authority alongside hand washing as a preventative measure against influenza.
A study from Penn State College of Medicine published in the Journal of Medical Virology in September 2020 found that several types of mouthwash and nasal rinses were effective at neutralizing human coronaviruses, suggesting that the products may have the potential to lessen the amount of SARS-CoV-2 load, or the amount of virus inside the mouth. SARS-CoV-2 is the virus that causes COVID-19.
A small pilot study is currently being conducted by the University of California, San Francisco on whether gargling with certain mouthwash or gargling solutions will reduce viral load in patients diagnosed with COVID-19. The study is expected to complete this September.
Gargling with antiseptic mouthwashes is part of the Front Line COVID-19 Critical Care (FLCCC) Alliance’s protocol for “both chronic (ongoing) prevention as well as to avoid getting sick” after an individual has been exposed to the virus.
FLCCC Alliance is a nonprofit organization consisting of critical care specialists who’ve dedicated their time to developing treatment protocols to “prevent the transmission of COVID-19 and to improve the outcomes for patients ill with the disease.”
As for the consumption of natto, soybeans that are fermented with a bacterium called bacillus subtillis or B. subtilliss, the researchers said that the participants who consumed the sticky soybeans, “had a significantly higher incidence of large white B. subtillis colonies on both sides of the masks than those who did not.”
B. subtillis is a bacterium found in soil, water, decomposing plant residue, and air. It is used for “industrial production of proteases, amylases, antibiotics, and specialty chemicals” and is “not considered pathogenic or toxigenic to humans, animals, or plants,” according to the U.S. Environmental Protection Agency (pdf).