Improving the efficacy of sewage treatment decreases norovirus contamination in oysters

Type Article
Date 2018-12
Language English
Author(s) Schaeffer Julien1, Treguier CathyORCID2, Piquet Jean-ComeORCID1, Gachelin Sonia3, Cochennec-Laureau NathalieORCID2, Le Saux Jean-Claude1, Garry PascalORCID1, Le Guyader Soizick1
Affiliation(s) 1 : Ifremer, Lab Microbiol, LSEM SG2M, Nantes, France.
2 : Ifremer, Lab Environm Ressources MPL, La Trinite Sur Mer, France.
3 : Com Reg Conchylicole Bretagne Sud, Auray, France.
Source International Journal Of Food Microbiology (0168-1605) (Elsevier Science Bv), 2018-12 , Vol. 286 , P. 1-5
DOI 10.1016/j.ijfoodmicro.2018.07.016
WOS© Times Cited 16
Keyword(s) Norovirus, Shellfish safety, Sewage treatment, Coastal water quality

As human population increases worldwide, water quality will become increasingly problematic, and food consumed raw may be of higher risk. This is already evident for oysters grown in coastal areas - despite regulations based on bacterial indicators, oysters are still implicated in food-borne outbreaks worldwide. The pathogens most frequently detected are human noroviruses, which are shed at high concentrations in human excreta and are very resistant to environmental conditions. Sewage treatment plants usually apply a variety of steps such as activated sludge treatment, chlorine or UV disinfection to eliminate contaminants, these processes have variable efficacy. This study demonstrates the impact of replacing an old lagoon-based sewage treatment plant with a new membrane bioreactor sewage treatment plant on human norovirus levels in treated sewage and oysters. While comparable norovirus concentrations were detected in the influent samples, a clear difference was observed in effluent quality, as norovirus was only detected in one sample after treatment in the new membrane bioreactor system, confirming the efficiency of such technology. As a direct impact, oysters located close to the membrane bioreactor sewage outfall were less frequently contaminated by norovirus, and showed lower concentrations compared to the first period of the study when they were exposed to sewage effluent from the lagoon outfall. Shellfish located upstream showed comparable contamination levels suggesting that there are also other sources of norovirus contamination in the estuary. Considering the health benefits of shellfish consumption, improving wastewater quality will make an important contribution to enhancing the safety of shellfish and international food

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Schaeffer Julien, Treguier Cathy, Piquet Jean-Come, Gachelin Sonia, Cochennec-Laureau Nathalie, Le Saux Jean-Claude, Garry Pascal, Le Guyader Soizick (2018). Improving the efficacy of sewage treatment decreases norovirus contamination in oysters. International Journal Of Food Microbiology, 286, 1-5. Publisher's official version : , Open Access version :