Purpose: This work aims to compare the baro-sensitivity of different rotavirus strains to HPP and to gain a better understanding of the correlation between strain difference and pressure resistance.
Methods: Four different rotavirus serotypes G1 (Wa, Ku, and K8 human strains), G2 (S2 human strain), G3 (SA-11 simian strain and YO human strain), and G4 (ST3 human strain) were treated at pressures ranging from 200 to 500 MPa at 4°C or 20°C for 2 min. The survival of rotavirus was quantified by plaque assay. The damage to viral structure and proteins was analyzed by electron microscope and SDS-PAGE, respectively.
Results : All rotavirus serotypes could be effectively inactivated (more than 5-log virus reduction) at pressure levels of 400-500 MPa for 2 min. Rotaviruses were more susceptible to HPP at 4°C compared to 20°C. Moreover, different strains of rotaviruses had different baro-sensitivity to HPP. Simian rotavirus SA-11 strain was more sensitive to HPP than human rotavirus strains. Furthermore, damage to virion structure by disruption of the viral capsid is the primary mechanism underlying HPP-induced viral inactivation. However, HPP did not degrade viral proteins or RNA.
Significance: Our results showed that (i) different rotavirus strains have different sensitivity to HPP; (ii) treatment temperature affects the effectiveness of viral inactivation; and (iii) damage of viral capsid is the primary mechanism underlying HPP inactivation of rotaviruses. This study also suggests HPP is a feasible technology to inactivate rotaviruses in food, water, and other fomites.