title: Electron beam inactivation of Tulane virus on fresh produce, and mechanism of inactivation of human norovirus surrogates by electron beam irradiation.
abstract: Ionizing radiation, whether by electron beams or gamma rays, is a non-thermal processing technique used to improve the microbial safety and shelf-life of many different food products. This technology is highly effective against bacterial pathogens, but data on its effect against foodborne viruses is limited. A mechanism of viral inactivation has been proposed with gamma irradiation, but no published study discloses a mechanism for electron beam (e-beam). This study had three distinct goals: 1) evaluate the sensitivity of a human norovirus surrogate, Tulane virus (TV), to e-beam irradiation in foods, 2) compare the difference in sensitivity of TV and murine norovirus (MNV-1) to e-beam irradiation, and 3) determine the mechanism of inactivation of these two viruses by e-beam irradiation. TV was reduced from 7 log10 units to undetectable levels at target doses of 16 kGy or higher in two food matrices (strawberries and lettuce). MNV-1 was more resistant to e-beam treatment than TV. At target doses of 4 kGy, e-beam provided a 1.6 and 1.2 log reduction of MNV-1 in phosphate buffered saline (PBS) and Dulbecco's Modified Eagle Medium (DMEM), compared to a 1.5 and 1.8 log reduction of TV in PBS and Opti-MEM, respectively. Transmission electron microscopy revealed that increased e-beam doses negatively affected the structure of both viruses. Analysis of viral proteins by SDS-PAGE found that irradiation also degraded viral proteins. Using RT-PCR, irradiation was shown to degrade viral genomic RNA. This suggests that the mechanism of inactivation of e-beam was likely the same as gamma irradiation as the damage to viral constituents led to inactivation.
authors.affiliation: Department of Food Science and Technology, College of Food, Agricultural, and Environmental Sciences, The Ohio State University, 2015 Fyffe Road, Parker Food Science Building, Columbus, OH 43210-1007, USA. Electronic address: Predmore.17@osu.edu.
authors.forename: Ashley
authors.initials: A
authors.lastname: Predmore
authors.affiliation: Department of Food Science and Technology, College of Food, Agricultural, and Environmental Sciences, The Ohio State University, 2015 Fyffe Road, Parker Food Science Building, Columbus, OH 43210-1007, USA.
authors.forename: Gabriel C
authors.initials: GC
authors.lastname: Sanglay
authors.affiliation: Department of Veterinary Biosciences, College of Veterinary Medicine, The Ohio State University, Goss Laboratory, 1925 Coffey Road, Columbus, OH 43210-1240, USA.
authors.forename: Erin
authors.initials: E
authors.lastname: DiCaprio
authors.affiliation: Department of Veterinary Biosciences, College of Veterinary Medicine, The Ohio State University, Goss Laboratory, 1925 Coffey Road, Columbus, OH 43210-1240, USA.
authors.forename: Jianrong
authors.initials: J
authors.lastname: Li
authors.affiliation: College of Technology, Kent State University, 375 Terrace Drive, Van Deusen Hall, Kent, OH 44242, USA.
authors.forename: R M
authors.initials: RM
authors.lastname: Uribe
authors.affiliation: Department of Food Science and Technology, College of Food, Agricultural, and Environmental Sciences, The Ohio State University, 2015 Fyffe Road, Parker Food Science Building, Columbus, OH 43210-1007, USA.
authors.forename: Ken
authors.initials: K
authors.lastname: Lee
mesh_terms: D000818:Animals; D002139:Caliciviridae / Q000528:radiation effects*; D017250:Caliciviridae Infections / Q000517:prevention & control; D004591:Electrophoresis, Polyacrylamide Gel; D005516:Food Microbiology / Q000379:methods*; D031985:Fragaria / Q000821:virology*; D018545:Lactuca / Q000821:virology*; D029322:Norovirus / Q000502:physiology / Q000528:radiation effects; D038301:Virus Inactivation
keywords: E-beam; Electron beam; Irradiation; Norovirus; Produce; Virus