Comparison of anti-SARS-CoV-2 activity of some commercial dairy products

The continuing emergence of new variants of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) could be ameliorated by infection prevention through daily diet. In this study, we examined the anti-SARS-CoV-2 activity of 10 commercially available dairy products. They did not show any cytotoxicity against VeroE6/transmembrane protease serine 2 (TMPRSS2) cells (CC₅₀ > 4 mg/ml). Importantly, these cells were checked using the cytopathic effect (CPE) assay, and 4 mg/ml dairy products reduced virus-induced CPE by more than 30%. Notably, Icreo akachan milk, an infant formula, showed the highest antiviral activity with an IC₅₀ of 1.4 mg/ml. We assessed the effects of the dairy products on the entry of SARS-CoV-2 pseudovirus. R1 and Yakult, lactic acid bacterial beverages, inhibited viral entry with IC₅₀ of 2.9 and 3.5 mg/ml, respectively. Collectively, these results indicate that commercially available dairy products moderately inhibit SARS-CoV-2 infection and may reduce the incidence of viral infections.