T6-09 High-pressure Processing of Rotaviruses: The Roles of Strain Diversity and Treatment Temperature in Virus Inactivation

Tuesday, July 24, 2012: 11:00 AM
Ballroom E (Rhode Island Convention Center)
Elbashir Araud, The Ohio State University, Columbus, OH
Fangfei Lou, The Ohio State University, Columbus, OH
Xinhui Li, University of Delaware, Newark, DE
Haiqiang Chen, University of Delaware, Newark, DE
Jianrong Li, The Ohio State University, Columbus, OH
Introduction:   Rotavirus is an important cause of acute gastroenteritis in infants and children worldwide. Rotavirus is a double-stranded RNA virus that is characterized by substantial genetic diversity. Currently, five serotypes (G1–G4, G9) predominate, accounting for almost 95% of strains worldwide. High-pressure processing (HPP) is a promising non-thermal processing technology to inactivate foodborne viruses.  However, whether HPP can effectively inactivate different rotavirus serotypes is not known.

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.