Inactivation of a Norovirus by High-Pressure Processing

Abstract

Murine norovirus (strain MNV-1), a propagable norovirus, was evaluated for susceptibility to high-pressure processing. Experiments with virus stocks in Dulbecco's modified Eagle medium demonstrated that at room temperature (20°C) the virus was inactivated over a pressure range of 350 to 450 MPa, with a 5-min, 450-MPa treatment being sufficient to inactivate 6.85 log 10 PFU of MNV-1. The inactivation of MNV-1 was enhanced when pressure was applied at an initial temperature of 5°C; a 5-min pressure treatment of 350 MPa at 30°C inactivated 1.15 log 10 PFU of virus, while the same treatment at 5°C resulted in a reduction of 5.56 log 10 PFU. Evaluation of virus inactivation as a function of treatment times ranging from 0 to 150 s and 0 to 900 s at 5°C and 20°C, respectively, indicated that a decreasing rate of inactivation with time was consistent with Weibull or log-logistic inactivation kinetics. The inactivation of MNV-1 directly within oyster tissues was demonstrated; a 5-min, 400-MPa treatment at 5°C was sufficient to inactivate 4.05 log 10 PFU. This work is the first demonstration that norovirus can be inactivated by high pressure and suggests good prospects for inactivation of nonpropagable human norovirus strains in foods.

Randomized, Double-Blinded Clinical Trial for Human Norovirus Inactivation in Oysters by High Hydrostatic Pressure Processing

“…The HuNoV surrogate, feline calicivirus (FCV), was inactivated up to 7 log 10 in tissue culture medium at a pressure of 275 MPa (11,18,26). Murine norovirus (MNV), another HuNoV surrogate, was reduced (4 log 10 ) in live oysters contaminated with MNV in seawater under simulated natural conditions (400 MPa, 5 min, 5°C) (25). The successful inactivation of HuNoV surrogates by HPP suggests that HuNoV may also be inactivated by HPP.…”

“…Final diluted inoculum aliquots were not quantified by quantitative RT-PCR (qRT-PCR) because they were too close to the qRT-PCR limit of detection for an accurate measure (36). The study team selected a dose of 1.0 ϫ 10 4 GEC for seeding of the oysters because published reports on norovirus contamination of oysters reported genogroup I norovirus contamination ranges of 966 to 1,690 GEC/g of oyster digestive tissue (33,34) and HPP was shown to inactivate 4 logs of murine norovirus (25). The HuNoV inoculum used in this study was tested for infectivity in a pilot study (n ϭ 7) prior to the start of phases 1 to 3.…”

“…HPP also serves a practical application by facilitating the shellfish shucking process by separating the meat from the shell and has been demonstrated to extend refrigerated shelf life (14,19,43). HPP has also been identified recently as a potential means for inactivating parasitic and viral pathogens such as Cryptosporidium parvum oocysts (12), hepatitis A virus, and HuNoV surrogates within raw shellfish (9,22,25,54). The HuNoV surrogate, feline calicivirus (FCV), was inactivated up to 7 log 10 in tissue culture medium at a pressure of 275 MPa (11,18,26).…”

“…The successful inactivation of HuNoV surrogates by HPP suggests that HuNoV may also be inactivated by HPP. Additionally, factors to consider that may influence HPP efficacy against noroviruses include the duration of pressure application, the temperature at which pressure is applied, and food matrix properties such as salinity, pH, and water content (11,23,25,26). If HPP is shown to inactivate HuNoV, the benefits of HPP paired with the potential inactivation of HuNoV in oysters would offer the shellfish industry an effective and multipurpose intervention against HuNoV contamination of oysters.…”

Effects of high hydrostatic pressure on Campylobacter jejuni in poultry meat

“…Nowadays, many researchers focus on the possibility of food-borne virus inactivation by the application of HPP technology (Kingsley et al 2007, Grove et al 2009, Tang et al 2010, Terio et al 2010, Gogal et al 2011, Kingsley 2013, which is especially important taking into consideration the possibility of simultaneous elimination of C. jejuni cells. According to presented study, current standard parameters (275-300 MPa for several minutes) applied to shellfish as a Vibrio control (Kingsley 2013) might be not efficient for C. jejuni reduction to a level considered as sufficient for consumer protection.…”