More than three-quarter of UK-grown oysters contain norovirus, according to Research published on Tuesday by the UK’s Food Standards Agency (FSA).
Described as a “first-of-its-kind” study, scientists from the Centre for Environment, Fisheries and Aquaculture Science (Cefas), on behalf of the FSA, collected samples from 39 oyster-harvesting areas across the UK between 2009 and 2011. More than 800 samples of 10 oysters each were tested.
The FSA emphasized that it is “difficult” to assess the potential health effects of the findings because it’s unable to differentiate between infectious and non-infectious norovirus material within the oysters. Furthermore, a safe limit for norovirus has not yet been established.
The highly infectious virus is commonly known as the “winter vomiting bug.” But the illness is generally mild and people usually recover fully within two to three days, and most norovirus infections are thought to spread from person to person and are not related oyster consumption, according to the FSA.
“Though oysters are traditionally eaten raw, people should be aware of the risks involved in eating them in this way,” said Andrew Wadge, FSA chief scientist. “The agency advises that older people, pregnant women, very young children and people who are unwell [to] avoid eating raw or lightly cooked shellfish to reduce their risk of getting food poisoning.”
Added Wadge, “The results, along with data from other research, will help us work with producers to find ways to reduce the levels of norovirus in shellfish, and work within Europe to establish safe levels.”
The Shellfish Association of Great Britain (SAGB) reacted to the study by emphasizing that the industry takes consumer protection “very seriously” by employing techniques to mitigate the risk of supplying infected shellfish to the marketplace. These techniques include regular norovirus testing, use of extended depuration (purification) times, increasing the temperature in the depuration tanks and cessation of harvesting in areas subject to heavy rain.
“The SAGB and industry is working extensively with FSA, Cefas, Environment Agency and water companies to further improve and understand the situation,” said the association.
The study garnered a lot of coverage by the UK media on Tuesday, including the BBC, The Telegraph, The Independent, The Guardian and The Daily Mail.
