Oyster

  • 76% of UK oysters have norovirus; ‘nothing here to say more or less risk, still some risk’

    Posted: November 29th, 2011 - 3:58pm by Doug Powell

    Research published today by the Food Standards Agency shows that a significant proportion (76%) of oysters tested from UK oyster growing beds contained norovirus. The virus was detected at low levels in more than half of the positive samples (52%).

    Dr Andrew Wadge, the FSA's chief scientist, told the BBC the research has not identified any new food safety risk.

    "If you are someone who enjoys eating raw oysters and you want to continue there is nothing here to say that you are at more risk or less risk. What we do say is that there is some risk."

    It is difficult to assess the potential health impact of these findings, as the available research techniques are not able to differentiate between infectious and non-infectious norovirus material within the oysters. Furthermore, a safe limit for norovirus has not been established.

    Between 2009 and 2011, scientists from the Centre for Environment, Fisheries and Aquaculture Science (Cefas), on behalf of the Food Standards Agency, took samples from 39 oyster harvesting areas across the UK. More than 800 samples of 10 oysters each were tested.

    Oysters filter large volumes of water to get their food, and any bacteria and viruses in the water can build up within the oyster. Controls before and after commercial harvesting of oysters, such as re-laying and depuration, provide good protection against harmful bacteria, but are less effective at removing viruses from live shellfish.

    Re-laying is a purification process used to treat bivalve shellfish. Shellfish are harvested from a contaminated area and moved to clean areas, where they are placed on the ocean floor or into containers laid on the ocean floor, or suspended in racks. Re-laying will generally be for at least two months.

    Depuration is a purification process used commercially and regulated by the Food Standards Agency. It is commonly used by producers to reduce or eliminate microbiological contamination in oysters and other shellfish. Shellfish are placed in tanks of clean re-circulating seawater, treated by UV irradiation, and allowed to purge their contaminants over several days. In the UK a minimum purification time of 42 hours is required.

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    food safety, fsa, norovirus, oyster, Uk
  • Heston stopped serving raw oysters; FDA links cholera outbreak to Florida raw oysters; at least 9 sick

    Posted: May 10th, 2011 - 1:32pm by Doug Powell

    raw.oyster.jpg

    After making 529 people sick in a March 2009 outbreak of norovirus at his Fat Duck restaurant, Heston Blumenthal says he has stopped serving raw oysters.

    At least that’s what he told the New Zealand Herald yesterday.

    "I've not served an oyster in here, in the Crown, in the Duck or in London since that happened. I don't know if I'll ever change."

    Today, the U.S. Food and Drug Administration advised consumers, restaurant operators, commercial shippers and processors of shellfish not to eat, serve, purchase, sell or ship oysters from Area 1642 in Apalachicola Bay, Fla. because the oysters may be contaminated with toxigenic Vibrio cholerae serogroup O75.

    • Nine persons have been reported with illness. For eight, the illness was confirmed as caused by toxigenic Vibrio cholerae O75; laboratory confirmation is pending in the other person. No one was hospitalized or died.

    • All ill persons reported consumption of raw or lightly steamed oysters.

    • Traceback indicates that oysters harvested from Area 1642 in Apalachicola Bay, Fla., between March 21 and April 6, 2011, are associated with illness.

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    Cholera, florida, food safety, heston, norovirus, oyster, Raw
  • To avoid norovirus don’t eat raw oysters

    Posted: January 26th, 2011 - 11:41am by Doug Powell

    The U.K. Food Standards Agency says to avoid norovirus, don’t eat oysters raw.

    They, however, use a lot more words.

    “Controls before and after commercial harvesting provide good protection against harmful bacteria, but it can be difficult to remove viruses from live shellfish. Thorough cooking will destroy these viruses but many shellfish are eaten raw or only lightly cooked so may still contain viruses when eaten. The FSA and the shellfish industry are continuing to work together to improve methods for removing viruses from live shellfish.”
     

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    food safety, norovirus, oyster, Raw, Uk
  • Norovirus in B.C oysters making people sick; government won’t say how many

    Posted: October 5th, 2010 - 5:06am by Doug Powell

    There are three separate clusters of norovirus associated with raw oysters making people barf in the Vancouver area (that’s in Canada) but, as usual, no details were provided by health types on actual numbers of people sick.

    CBC News reports the B.C. Centre for Disease Control has confirmed that an outbreak of illness related to eating uncooked Pacific Coast oysters is being caused by a norovirus.

    The affected oysters have been traced to a section of Effingham Inlet on the west coast of Vancouver Island. The oysters were harvested between Sept. 7 and Sept. 21.

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    bc, Canada, Illness, norovirus, oyster, Vancouver, Vomit
  • Raw oysters still risky

    Posted: September 15th, 2010 - 12:25pm by Doug Powell

    September may be a ‘R’ month but the Gulf of Mexico is still warm. I know. We’re still here. So is Vibrio vulnificus.

    The Sarasota Herald Tribune reports the Florida Department of Health is warning heavy drinkers and people with liver damage to avoid eating raw oysters or exposing open wounds to still-warm Gulf and bay waters.

    So far this year, six deaths from Vibrio vulnificus infection have been reported in Florida. The DOH has determined that at least two of the deaths were attributed to raw oyster consumption. Eight wound infections have been reported, but none were fatal.

    Thoroughly cooking oysters — frying, stewing, or roasting them — eliminates harmful bacteria and viruses, says the DOH.
     

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    Other Microorganisms  |  1 Comment
    gulf, liver, oyster, Raw, Risk, Vibrio
  • Dozens barf after eating raw Oregon oysters covered in norovirus

    Posted: March 4th, 2010 - 10:15pm by Doug Powell

    The Oregonian – what else to all a publication from Oregon – reports Oregon scientists have confirmed that three people who ate raw oysters harvested from Yaquina Bay were sickened by norovirus.

    The positive lab results follow reports of 16 people in Oregon, Washington and Massachusetts who got sick after eating the oysters, said Meredith Vandermeer, epidemiologist with the Public Health Division.

    Dawn Smith, food safety specialist with the Department of Agriculture, said that all of the suspect oysters in the U.S. have been pulled off the marketplace.

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  • 42 St. Oyster Bar outbreak climbs to 280 ill; norovirus isolated from three patrons

    Posted: January 7th, 2010 - 12:00am by Ben Chapman

    Author: 
    Ben Chapman

    Initially reported as an outbreak of foodborne illness among 30 patrons, WRAL reports tonight that up to 280 people have reported becoming ill after eating at Raleigh's 42 St. Oyster Bar in late December. Health authorities also believe that illnesses also might not have been linked to oysters as initially reported. As Norovirus is easily transmissible and needs only a few particles to infect, it will be difficult for investigators to pinpoint the initial source. Health authorities tested eight employees for norovirus and all have been negative for the virus.

    42nd Street owner Brad Hurley initially thought the culprit was oysters from Louisiana. As a precaution, the restaurant immediately stopped serving the Louisiana oysters and started using only oysters from North Carolina.

    Tests of the remaining Louisiana oysters have come back negative, Andre Pierce, Wake County's environmental health and safety director said.

    The restaurant has also worked with the health department to take other precautions, such as eliminating bare hand contact with food and changing from an ammonia sanitizer to chlorine.

    Pierce said they may never know the exact source.

    "Norovirus is probably one of the most unreported food illnesses out there. It's hard to detect. It's hard to find a source. We spend a lot of time and resources trying to track it down. And it is frustrating to us and it is frustrating to the public that you can't just put a finger on it, but it is very present and I think it's a lot more out there than we realize."

    Public vomiting is particularly a problem as the act of spewing can cause particles to spread. Norovirus particles can also stay viable on surfaces for weeks. Pathogens can be passed on by someone even if they aren’t feeling ill. In 2008 a foodhandler who did not show symptoms or test positive for Norovirus caused an outbreak leading to over 30 illnesses. It's believed that the foodhandler, who was caring for ill family members at home, introduced the norovirus into the kitchen by practicing poor personal hygiene.

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    42, Bar, Outbreak, oyster, Raleigh, St.