Bacterial and fungal isolation from face masks under the Covid-19 pandemic

Note this study points to the importance of continuing with handwashing routines, which reduce the transmission of a wide variety of infectious diseases.

> "We detected B. cereus, a foodborne pathogen, on the outer-side of masks in 5% of the participants (Fig. 4c), suggesting that B. cereus might adhere to the face masks through hands from feces. Intensive handwashing is recommended, since handwashing is effective in reducing the incidence of diarrhea."

> Natto is a traditional Japanese fermented food that is sticky when eaten and clings to the mouth and chopsticks (Fig. 3c). Natto is made by fermenting soybeans with the spore-forming bacterium Bacillus subtilis, which can survive dry conditions. As expected, in this study, we observed the large white colonies formed by B. subtilis. According to the questionnaire, 9% and 27% of the participants have eaten natto daily and weekly, respectively; 19% of the participants ate natto during the experimental period. The participants who ate natto had a significantly higher incidence of large white B. subtilis colonies on both sides of the masks than those who did not.

The authors have this bizarre obsession with reminding us of all the Japanese things going on in the study, and it culminates in borderline parody here.

Study examines bacterial and fungal exposures from repeated or prolonged mask usage.

"..we found [increases in] several pathogenic microbes; Bacillus cereus, Staphylococcus saprophyticus, Aspergillus, and Microsporum..."

"We propose that immunocompromised people should avoid repeated use of masks to prevent microbial infection."

Nothing too alarming, but kind of what you'd expect putting something on your face.

tl;dr - Wear a fresh mask.