Technicians at a lab in Singapore demonstrate how they test and certify surgical masks during a media tour. Masks sent to the lab by clients are tested for bacterial filtration, particle filtration, breathability, liquid penetration and flame resistance. To test for bacterial filtration, a bacterial culture medium is sprayed onto a mask with a petri dish underneath. Singapore-based company Setsco Services began testing surgical masks this year after coronavirus outbreaks began and has since tested masks from 20 clients. /AFP