T6-07 High Pressure Processing of Human Norovirus Virus-like Particles: Evidence That Human Norovirus May be Highly Pressure Resistant

Tuesday, July 24, 2012: 10:30 AM
Ballroom E (Rhode Island Convention Center)
Fangfei Lou, The Ohio State University, Columbus, OH
Pengwei Huang, Cincinnati Children's Hospital Medical Center, Cincinnati, OH
Hudaa Neetoo, University of Delaware, Newark, DE
Joshua Gurtler, U.S. Department of Agriculture-ARS, Wyndmoor, PA
Brendan Niemira, U.S. Department of Agriculture-ARS, Wyndmoor, PA
Haiqiang Chen, University of Delaware, Newark, DE
Xi Jiang, Cincinnati Children's Hospital Medical Center, Cincinnati, OH
Jianrong Li, The Ohio State University, Columbus, OH
Introduction:  High pressure processing (HPP) is a promising non-thermal technology for inactivating foodborne viruses; nevertheless, the effectiveness of HPP on inactivating human norovirus (HuNoV), the leading cause of acute gastroenteritis, is unknown because it cannot be propagated in cell culture. Developing a new model system, therefore, to understand the survival of HuNoV is urgently needed.

Purpose:  The objective of this study was to evaluate the stability of HuNoV capsid to HPP using virus-like particles (VLPs) as a model.

Methods:  HuNoV VLPs were treated at pressures ranging from 500 to 900 MPa at 4 °C for various holding times (between 1 and 60 min). HuNoV capsid disruption was evaluated by analyzing VLP structure integrity, and binding to its functional receptors, histo blood group antigens (HBGAs).

Results:  Pressurization at 500-600 MPa, the pressure known to completely inactivate HuNoV surrogates (e.g., murine norovirus [MNV] and feline calicivirus [FCV]) in 2 min, was not sufficient to disrupt the structure and function of HuNoV VLPs, even with a holding time of 60 min. Disrupting efficacy of HPP increased with increasing pressures. Times required for complete disruption of HuNoV VLPs at 700, 800, and 900 MPa were 30, 10, and 2 min, respectively. Moreover, HuNoV VLPs were more resistant to HPP in their ability to bind type A than types B and O HBGAs. Additionally, the sub-VLPs (23-nm) appeared to be much more stable than the full size VLPs (38-nm).

Significance:  While high levels of pressure (800-900 MPa) are required, a short holding time is capable of disrupting HuNoV VLPs. Our data suggest that HuNoV may be more resistant to HPP than MNV and FCV; therefore, the HuNoV VLPs may be a better model to study the survival of HuNoV under various conditions and further facilitate the use of HPP to inactivate pathogenic viruses, thereby improving the safety of high risk foods.