Persistence of Hepatitis A Virus in Oysters

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131

, J. Food Prot. 65:1605-1609, 2002); however, direct evaluation of HAV inactivation within contaminated oysters was not performed. In this study, we report confirmation that HAV within contaminated shellfish is inactivated by HHP. Shellfish were initially contaminated with HAV by using a flowthrough system. PFU reductions of >1, >2, and >3 log 10 were observed for 1-min treatments at 350, 375, and 400 megapascals, respectively, within a temperature range of 8.7 to 10.3°C. Bioconcentration of nearly 6 log 10 PFU of HAV per oyster was achieved under simulated natural conditions. These results suggest that HHP treatment of raw shellfish will be a viable strategy for the reduction of infectious HAV.

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confidence: 99%

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confidence: 99%

High-Pressure Inactivation of Hepatitis A Virus within Oysters

Calci

Meade

Tezloff

et al. 2005

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131

“…Beyond cooking, there currently is no adequate intervention for bivalve shellfish contaminated with enteric viruses because these viruses can remain within shellfish for periods beyond a few days (16,24,27,35). Although some nonenveloped viruses are less sensitive or even completely resistant to pressures as high as 600 MPa (19,22,37), HPP has shown promise for inactivation of hepatitis A virus (HAV) and norovirus surrogate viruses.…”

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confidence: 99%

Inactivation of a Norovirus by High-Pressure Processing

Kingsley

Holliman

Calci

et al. 2007

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178

133

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.

“…Depuration is a dynamic process whereby shellfish are allowed to purge themselves of contaminants either in a natural setting or in land-based facilities, whereas relaying is the practice of transferring shellfish harvested from contaminated areas to clean shellfish-growing waters (31). Data on virus persistence are needed to address how long viruses may persist in contaminated oyster beds so that early reopening of beds that might pose a risk to the health of consumers can be prevented.Working with live bivalve mollusks under laboratory conditions may introduce artificial parameters that do not adequately account for environmental factors (i.e., nutriments, temperature, or suspended matter, which can modify filtration rates) important for interpretation of results (8,17,27,31,33,35). The use of large depuration tanks and professional equipment allows better reliability and reproducibility of different environmental parameters (aeration, UV, water quality, speed of water recycling, temperature, disinfection of wastewater).…”

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confidence: 99%

“…Working with live bivalve mollusks under laboratory conditions may introduce artificial parameters that do not adequately account for environmental factors (i.e., nutriments, temperature, or suspended matter, which can modify filtration rates) important for interpretation of results (8,17,27,31,33,35). The use of large depuration tanks and professional equipment allows better reliability and reproducibility of different environmental parameters (aeration, UV, water quality, speed of water recycling, temperature, disinfection of wastewater).…”

mentioning

confidence: 99%

Use of Rotavirus Virus-Like Particles as Surrogates To Evaluate Virus Persistence in Shellfish

Loisy

Atmar

Saux

et al. 2005

Rotavirus virus-like particles (VLPs) and MS2 bacteriophages were bioaccumulated in bivalve mollusks to evaluate viral persistence in shellfish during depuration and relaying under natural conditions. Using this nonpathogenic surrogate virus, we were able to demonstrate that about 1 log 10 of VLPs was depurated after 1 week in warm seawater (22°C). Phage MS2 was depurated more rapidly (about 2 log 10 in 1 week) than were VLPs, as determined using a single-compartment model and linear regression analysis. After being relayed in the estuary under the influence of the tides, VLPs were detected in oysters for up to 82 days following seeding with high levels of VLPs (concentration range between 10 10 and 10 9 particles per g of pancreatic tissue) and for 37 days for lower contamination levels (10 5 particles per g of pancreatic tissue). These data suggest that viral particles may persist in shellfish tissues for several weeks.Bivalve mollusks may accumulate viral contaminants within their tissues during feeding, and outbreaks of viral gastroenteritis and hepatitis have been associated with oyster consumption (19,21,34) and even with depurated shellfish (15,16,30). Virus uptake by shellfish occurs rapidly (less than 24 h of exposure) following contact with sewage or seeded contaminated waters (3,4,11,12,19,31,33). However, little is known about viral persistence following depuration or relaying. Depuration is a dynamic process whereby shellfish are allowed to purge themselves of contaminants either in a natural setting or in land-based facilities, whereas relaying is the practice of transferring shellfish harvested from contaminated areas to clean shellfish-growing waters (31). Data on virus persistence are needed to address how long viruses may persist in contaminated oyster beds so that early reopening of beds that might pose a risk to the health of consumers can be prevented.Working with live bivalve mollusks under laboratory conditions may introduce artificial parameters that do not adequately account for environmental factors (i.e., nutriments, temperature, or suspended matter, which can modify filtration rates) important for interpretation of results (8,17,27,31,33,35). The use of large depuration tanks and professional equipment allows better reliability and reproducibility of different environmental parameters (aeration, UV, water quality, speed of water recycling, temperature, disinfection of wastewater). However, under such conditions, the potential environmental impact of live enteric viruses precludes their use, even when the viruses are of animal origin.Coexpression of viral capsid proteins in the baculovirus expression systems results in the assembly of virus-like particles (VLPs) that maintain the structural and functional characteristics of the native particles: they resemble a real virus, but they are noninfectious (9). These VLPs have been helpful in fundamental research (7, 13) but also in environmental persistence and inactivation studies (5, 22) and in monitoring the fate and transport of viruses ...