Background and purpose: Since long time ago herbal products and spices have been used as powders, essential oils (EOs), and extracts. They consist of antimicrobial components and could be applied as natural food preservatives. In the present work, the antiviral effect of cinnamon, rosemary, and zataria EOs has been investigated against norovirus surrogates including feline calicivirus (FCV) and murine norovirus (MNV).

Materials and methods: Different concentrations of EOs were individually mixed with each virus at titers of ca. 7-8 log TCID50/ml and incubated for 2 h at 4ºC and 37 ºC. The infectivity of the recovered viruses was evaluated by cell-culture assays.

Results: At 37 ºC, 3% of cinnamon, 2.5% of rosemary and 0.1% of zataria EOs decreased the FCV titers by 2. 38, 3.38, and 4.51 log TCID50/ml, respectively. At lower concentrations they were found to be less effective. Also, different concentrations of EOs decreased MNV titers by 0.25-1.44 log TCID50/ml. The maximum titer reduction (4.51 log TCID50/ml) was achieved when the FCV was treated at 37 ºC with 0.1% of zataria EO.

Conclusion: The reduction on the infectivity titers found for the tested norovirus surrogates with these EOs highlighted their potential role as biopreservatives to improve food hygiene and shelflife.