Scientific Opinion on Norovirus (NoV) in oysters: methods, limits and control options

Abstract NoV is highly infectious, and there is no threshold infectivity limit for NoV detected by PCR. The probability of becoming infected increases with the dose but depends also on the characteristics of the organism, the food matrix and the host factors. The relationship between the number of i...

Full description

Saved in:
Bibliographic Details
Main Author: EFSA Panel on Biological Hazards (BIOHAZ)
Format: Article
Language:English
Published: Wiley 2012-01-01
Series:EFSA Journal
Subjects:
Online Access:https://doi.org/10.2903/j.efsa.2012.2500
Tags: Add Tag
No Tags, Be the first to tag this record!
_version_ 1850220175434973184
author EFSA Panel on Biological Hazards (BIOHAZ)
author_facet EFSA Panel on Biological Hazards (BIOHAZ)
author_sort EFSA Panel on Biological Hazards (BIOHAZ)
collection DOAJ
description Abstract NoV is highly infectious, and there is no threshold infectivity limit for NoV detected by PCR. The probability of becoming infected increases with the dose but depends also on the characteristics of the organism, the food matrix and the host factors. The relationship between the number of infectious virus particles and the number of virus genome copies detected by quantitative PCR is not a constant, and it is important to realise that the infectious risk associated with low level positive oysters as determined by real‐time PCR may be overestimated. Quantitative data on viral load from areas compliant with current EU legislative requirements (E. coli standards) during January‐March 2010 in 3 selected member states, show that a viral limit of 100, 200, 500, 1000 or 10.000 NoV PCR copies would result in 33.6‐88.9%, 24.4‐83.3%, 10.0‐72.2%, 7.7‐44.4% or 0‐11.1% of non‐compliant batches, respectively. Compliance with any of the above NoV limits would reduce the number of contaminated oysters placed on the market and therefore the risk for consumers to become infected. It is currently not possible to quantify the public health impact of different limits. Microbiological criteria for NoV in oysters are useful for validation and verification of HACCP‐based processes and procedures, and can also be used by competent authorities as an additional control to improve risk management in production areas, during processing and retail. The Panel recommended that risk managers should consider establishing an acceptable limit for NoV in oysters to be harvested and placed on the market. NoV testing of oysters (standardized CEN method) should be used to verify compliance with the acceptable NoV limit established. The most effective public health measure to control human NoV infection from oyster consumption is to produce oysters from areas which are not faecally contaminated, particularly given the ineffectiveness of current depuration and relaying procedures.
format Article
id doaj-art-80a255ddb6fc4a72bd50a263a83c0b67
institution OA Journals
issn 1831-4732
language English
publishDate 2012-01-01
publisher Wiley
record_format Article
series EFSA Journal
spelling doaj-art-80a255ddb6fc4a72bd50a263a83c0b672025-08-20T02:07:09ZengWileyEFSA Journal1831-47322012-01-01101n/an/a10.2903/j.efsa.2012.2500Scientific Opinion on Norovirus (NoV) in oysters: methods, limits and control optionsEFSA Panel on Biological Hazards (BIOHAZ)Abstract NoV is highly infectious, and there is no threshold infectivity limit for NoV detected by PCR. The probability of becoming infected increases with the dose but depends also on the characteristics of the organism, the food matrix and the host factors. The relationship between the number of infectious virus particles and the number of virus genome copies detected by quantitative PCR is not a constant, and it is important to realise that the infectious risk associated with low level positive oysters as determined by real‐time PCR may be overestimated. Quantitative data on viral load from areas compliant with current EU legislative requirements (E. coli standards) during January‐March 2010 in 3 selected member states, show that a viral limit of 100, 200, 500, 1000 or 10.000 NoV PCR copies would result in 33.6‐88.9%, 24.4‐83.3%, 10.0‐72.2%, 7.7‐44.4% or 0‐11.1% of non‐compliant batches, respectively. Compliance with any of the above NoV limits would reduce the number of contaminated oysters placed on the market and therefore the risk for consumers to become infected. It is currently not possible to quantify the public health impact of different limits. Microbiological criteria for NoV in oysters are useful for validation and verification of HACCP‐based processes and procedures, and can also be used by competent authorities as an additional control to improve risk management in production areas, during processing and retail. The Panel recommended that risk managers should consider establishing an acceptable limit for NoV in oysters to be harvested and placed on the market. NoV testing of oysters (standardized CEN method) should be used to verify compliance with the acceptable NoV limit established. The most effective public health measure to control human NoV infection from oyster consumption is to produce oysters from areas which are not faecally contaminated, particularly given the ineffectiveness of current depuration and relaying procedures.https://doi.org/10.2903/j.efsa.2012.2500Norovirusoystersdiagnostic methodsmicrobiological criteriatreatmentcontrol
spellingShingle EFSA Panel on Biological Hazards (BIOHAZ)
Scientific Opinion on Norovirus (NoV) in oysters: methods, limits and control options
EFSA Journal
Norovirus
oysters
diagnostic methods
microbiological criteria
treatment
control
title Scientific Opinion on Norovirus (NoV) in oysters: methods, limits and control options
title_full Scientific Opinion on Norovirus (NoV) in oysters: methods, limits and control options
title_fullStr Scientific Opinion on Norovirus (NoV) in oysters: methods, limits and control options
title_full_unstemmed Scientific Opinion on Norovirus (NoV) in oysters: methods, limits and control options
title_short Scientific Opinion on Norovirus (NoV) in oysters: methods, limits and control options
title_sort scientific opinion on norovirus nov in oysters methods limits and control options
topic Norovirus
oysters
diagnostic methods
microbiological criteria
treatment
control
url https://doi.org/10.2903/j.efsa.2012.2500
work_keys_str_mv AT efsapanelonbiologicalhazardsbiohaz scientificopiniononnorovirusnovinoystersmethodslimitsandcontroloptions