Skip to main content
ARS Home » Northeast Area » Wyndmoor, Pennsylvania » Eastern Regional Research Center » Food Safety and Intervention Technologies Research » Research » Publications at this Location » Publication #315015
Title: A gnotobiotic pig model for determining human norovirus inactivation by high-pressure processing

Author
item LOU, FANGFEI - The Ohio State University
item YE, MU - University Of Delaware
item MA, YUANMEI - The Ohio State University
item LI, XINHUI - University Of Delaware
item DICAPRIO, ERIN - The Ohio State University
item CHEN, HAIQIANG - University Of Delaware
item KRAKOWKAL, STEVEN - The Ohio State University
item HUGHES, JOHN - The Ohio State University
item Kingsley, David
item LI, JIANRONG - The Ohio State University

Submitted to: Applied and Environmental Microbiology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/17/2015
Publication Date: 10/1/2015
Citation: Lou, F., Ye, M., Ma, Y., Li, X., Dicaprio, E., Chen, H., Krakowkal, S., Hughes, J., Kingsley, D.H., Li, J. 2015. A gnotobiotic pig model for determining human norovirus inactivation by high-pressure processing. Applied and Environmental Microbiology. 81(19):6679-6687.

Interpretive Summary: This study compares inactivation obtained by high pressure processing (HPP), a nonthermal food intervention technology by two separate assays. The first is the porcine gastric mucin-magnetic bead assay (PGM-MB) which assesses the ability of human norovirus to bind to receptor-like molecules isolated from swine intestines. If the virus cannot bind, it is considered inactivated. The second assay is a live animal model using gnotobiotic pigs. Essentially these are immunologically naive piglets that have been delivered by Caesarian section. Results of the study show that the PGM-MB assay and the gnotobiotic pig assay are roughly equivalent. Furthermore, inactivation of GII.4 human norovirus is demonstrated, showing that HPP inactivates this strain of virus efficiently.

Technical Abstract: Human norovirus (NoV) is responsible for over 90 percent of outbreaks of acute nonbacterial gastroenteritis worldwide, and accounts for 60 percent of foodborne illness in the US. Currently, the infectivity of human NoVs is poorly understood due to the lack of a cell culture system. In this study, we determined the survival of a human NoV GII.4 strain in seeded oyster homogenate after high pressure processing (HPP) using a novel receptor binding assay and a gnotobiotic pig model. Pressure condition of 350 MPa at 0 degrees C for 2 min led to a 3.7 log reduction in viral RNA copies in oysters measured by the porcine gastric mucin conjugated magnetic beads (PGM-MBs) binding assay and real time RT-PCR whereas 350 MPa at 35 degrees C for 2 min only achieved 1 log reduction in RNA copies. Newborn gnotobiotic piglets orally fed oyster homogenate treated at 350 MPa at 0 degrees C for 2 min did not have viral RNA shedding in feces, histologic lesions, or viral replication in the small intestine. In contrast, gnotobiotic pigs fed oysters treated at 350 MPa at 35 degrees C for 2 min had high levels of viral shedding in feces and exhibited significant histologic lesions and viral replication in the small intestine. Collectively, these data demonstrated that (i) human NoV survival estimated by an in vitro PGM-MBs viral binding assay was consistent with the infectivity determined by an in vivo gnotobiotic pig model; and (ii) HPP is capable of inactivating a human NoV GII.4 strain at commercially acceptable pressure levels.