Screening Commercial Tea for Rapid Inactivation of Infectious SARS-CoV-2 in Saliva

The objective of this study was to identify commercially available teas that can rapidly inactivate infectious SARS-CoV-2 in saliva. Initially, tea (n = 24) was prepared as 40 mg/mL infusions and incubated with SARS-CoV-2 resuspended in water, for 5 min at 37 °C. Then, five teas that showed >3 log reduction in virus infectivity were further investigated at 40 and 10 mg/mL infusions for 60 and 10 s contact time with SARS-CoV-2 resuspended in saliva. Tea polyphenols were measured using the Folin-Ciocalteu assay. SARS-CoV-2 infectivity was quantified on Vero-E6 cell line using TCID50 assay. At 10 mg/mL infusion, black tea showed the highest reduction (3 log, i.e., 99.9%) of infectious SARS-CoV-2 within 10 s. Green, mint medley, eucalyptus-mint, and raspberry zinger teas showed similar inactivation of SARS-CoV-2 (1.5 –2 log, i.e., 96–99% reduction). At 40 mg/mL infusions, all five teas showed >3 log reduction in virus infectivity within 10 s. Tea polyphenol but not pH was significantly correlated to virus reduction. Time-of-addition assay revealed that the five teas displayed preventive effects (0.5 –1 log, i.e., 68–90% reduction) against SARS-CoV-2 infection of Vero-E6 cells as well as during post-virus infection (1.2–1.9 log, i.e., 94–98%). However, the highest inhibitory effect was observed when the teas were added at the time of virus infection (2–3 log, i.e., 99–99.9%). Our res ults provide insights into a rapid at-home intervention (tea drinki...
Source: Food and Environmental Virology - Category: Virology Source Type: research