Oysters and shellfish sold at market. (Photo: Stock File)
Almost 70pct of oysters sold in the UK contain norovirus
Wednesday, May 16, 2018, 00:10 (GMT + 9)
Contaminated oysters poison 12,000 Britons a year with more than two-thirds of the shellfish on sale infected with the contagious norovirus, according to new findings from two studies.
On the one hand, researchers at the Centre for Applied Marine Sciences on Anglesey found oysters were causing about 11,800 cases of norovirus poisoning per year in the UK.
On the other hand, scientists at the Centre for Environment, Fisheries and Aquaculture Science (CEFAS) looked at more than 600 samples sold in supermarkets over 12 months.
According to these scientific study results, published in the journal Food and Environmental Virology, human sewage and farm waste released into the sea have been identified as the source of the toxic norovirus, which does not occur naturally in the shellfish.
James Lowther of the CEFAS said he and his team had analysed 630 oysters bought online and from shops and restaurants in the UK and concluded that the virus had been present in 69 per cent of samples.
“Contamination of bivalve shellfish, particularly oysters, with norovirus is recognised as a food safety risk,” Lowther warned.
Scientists grouped the oysters based on where they had come from. Those caught off the coast of Holland carried fewest viruses, probably because the Dutch allow less raw sewage into the sea. However, around the UK, more than 60 per cent of oyster production areas were classified as being contaminated.
Cleanliness of oysters has been recognised as a public health issue for several years but tests only measure numbers of the E coli bacteria. Most of them pass this – but the greater risk of norovirus is currently ignored.
Official statistics reveal that in total, there were 145 norovirus outbreaks across England between January and March of this year. 4,100 additional cases were reported between last autumn and March, although the overall number of cases is likely to much higher, given that most sufferers do not bother to visit their doctor.
Nevertheless, David Jarrad from the Shellfish Association of Great Britain (SAGB) refutes the findings and insists: “You’re more likely to get ill from eating salad than oysters.”