Oysters

  • Posted: July 21st, 2012 - 10:42pm by Doug Powell

    Those same Korean oysters the U.S. banned because of norovirus sickened at least 62 people who dined at three different outlets of a well-known chain buffet restaurant in China in June.

    According to China NewsNow, the Department of Health will fine the importer NT60 000 to 6 mil and 150,000 oysters prohibited from sale have been ordered to be destroyed.

    The U.S. Food and Drug Administration also reiterated earlier advice Friday not to eat raw or partially cooked oysters and clams (shellfish) with tags listing Oyster Bay Harbor, in Nassau County, N.Y., as the harvest area, following illnesses reported in several states caused by Vibrio parahaemolyticus bacteria.

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  • Posted: June 30th, 2012 - 7:16pm by Doug Powell

    I don’t know any food microbiologists who eat raw oysters; they may exist, but maybe I only know the drunks and they know better than to play with Vibrio and its liver-specific toxins.

    And every time we post something about raw oysters, producers and government-types say we have no idea what we’re talking about – and provide no data.

    So this isn’t me, it’s from the Washington state department of health via Seattlepi, which is telling Washingtonians to thoroughly cook their oysters.

    The department says that cooking shellfish until the shells open is not enough for kill harmful bacteria.

    Summer's warmer temperatures mean that levels of the bacteria Vibrio parahaemolyticus increase in state waters. Eating an oyster with the Vibrio bacteria can lead to diarrhea, stomach cramps, nausea, vomiting, headache, fever, and chills. It says that symptoms usually appear within 12-24 hours after eating infected shellfish and usually last from two to seven days.

    The department recommends oysters should be cooked to an internal temperature of 145 degrees for at least 15 seconds to thoroughly kill the bacteria.

    Yes, I temp my oysters with a thermometer. Because I know a few drunks and don’t want to kill them.

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  • Posted: February 19th, 2012 - 12:30am by Ben Chapman

    Author: 
    Ben Chapman

    There are lots of food safety myths floating around like color is a good indicator of safe temperatures or the 3-second rule. One that popped up last week in a class I was guest lecturing in: freezing food kills things. I think this comes from some old parasite-reducing practices (fish especially) but someone asked specifically about shellfish - and whether freezing things like oysters, shrimp or clams does anything. Depends on the target pathogen, the risks with oysters specifically are viral (Noro or Hep A). So freezing might do something for the worms, but it's not going to do much of anything to reduce viruses.

    In this week's Morbidity and Mortality Weekly Report (still my favorite publication title) investigators discuss a Washington State outbreak associated with frozen raw oysters.

    Some highlights:

    On October 19, 2011, Public Health – Seattle & King County was contacted regarding a woman who had experienced acute gastroenteritis after dining at a local restaurant with friends. Staff members interviewed the diners and confirmed that three of the seven in the party had consumed a raw oyster dish. Within 18–36 hours after consumption, the three had onsets of aches, nausea, and nonbloody diarrhea lasting 24–48 hours. One ill diner also reported vomiting. The four diners who had not eaten the raw oysters did not become ill.

    An inspection of a walk-in freezer at the restaurant revealed eight 3-pound bags of frozen raw oysters, which the restaurant indicated had been an ingredient of the dish consumed by the ill diners. The oysters had been imported from South Korea by company A and shipped to a local vendor, which sold them to the restaurant. All eight bags were sent to the Food and Drug Administration's Gulf Coast Seafood Laboratory for norovirus testing and characterization by real-time reverse transcription–polymerase chain reaction (rRT-PCR).

    A stool specimen from one of two ill diners collected 17 days after symptom onset tested positive for norovirus; sequence analysis identified GI.1 and GII.17 strains. Sequence analysis of the oysters identified a GII.3 strain. Because oysters can harbor multiple norovirus strains that are unequally amplified by rRT-PCR, discordance between stool specimens and food samples in shellfish-associated norovirus outbreaks is common and does not rule out an association. On November 4, 2011, company A recalled its frozen raw oysters.

    The frozen oysters implicated in this outbreak were distributed internationally and had a 2-year shelf-life.
    Such contamination has potential for exposing persons widely dispersed in space and time, making cases difficult to identify or link through traditional complaint-based surveillance

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  • Posted: January 17th, 2012 - 1:27pm by Doug Powell

     The most effective public health measures to protect consumers from exposure to norovirus in oysters are to produce oysters in areas which are not contaminated or to prevent contamination of mollusc production areas.

    And current methods used to remove norovirus in shellfish are not an effective means of reducing contamination.

    So says the European Food Safety Authority (EFSA) Panel on Biological Hazards (BIOHAZ Panel) in a new risk assessment.

    The Panel recommends establishing acceptable limits for the presence of virus in oysters that are harvested and placed on the market in the European Union. In addition, an EU-wide baseline survey on norovirus in oysters should be carried out to provide information on overall consumer exposure as well as the public health impact of control measures.

    Norovirus is transmitted through the consumption of food or water contaminated with fecal matter or through person-to-person contact or contact with infected surfaces. Oysters contaminated with norovirus pose a particular risk to human health as they are often consumed raw.

    EFSA’s BIOHAZ Panel concludes that norovirus is highly infectious and that the amount of the virus detected in oysters linked to human cases can vary greatly.

    Scientists highlight that norovirus is frequently detected in oysters in Europe which comply with existing EU control standards for bivalve molluscs.

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  • Posted: December 3rd, 2011 - 5:53am by Doug Powell

    By March 2009, 529 diners had become sick with norovirus from raw oysters served by Fat Duck proprietor and pseudo-celebrity, Heston Blumenthal.

    From the beginning of the outbreak, Blumenthal blamed others – especially the suppliers – failing to recognize that as owner and chef, he determines what is served, and his business, with consumers who fork over hundreds of pounds for a meal, is based almost entirely on trust.

    When health-types noted a number of staff were working while sick, Blumenthal employed the but-we-have-a-manual defense, which is nothing more than an invitation for more derision.

    When Blumenthal did finally issue an apology on September 25, 2009—seven months after the outbreak was discovered and more than two weeks after the U.K. Health Protection Agency issued a report on the outbreak—it suggested that he viewed an empathetic apology as an admission of guilt.

    "I am relieved to be able to finally offer my fullest apologies to all those who were affected by the outbreak at the Fat Duck,” said Blumenthal, “It was extremely frustrating to not be allowed to personally apologise (sic) to my guests until now. It was devastating to me and my whole team, as it was to many of our guests and I wish to invite them all to return to the Fat Duck at their convenience [for a free meal]."

    The apology was too late and again failed to accept responsibility for the aspects of the outbreak that were under the chef’s control—namely, acquiring seafood from unsafe sources and allowing sick employees to handle food.

    Television presenter Jim Rosenthal, who was sickened, called Blumenthal’s response, “pathetic.”



    “He has basically attempted to re-write the HPA report and its conclusions in his favour. It is pathetic and a complete PR disaster. There isn’t even a hint of apology."

    Last week, investigators published the results of the investigation in a peer-reviewed journal, Epidemiology and Infection.

    According to the paper, HPA received notification of four individuals who had developed symptoms of diarrhea and vomiting on Feb. 25, 2009, after a local health authority received notification from private consultants late on Feb. 24, 2009. The consultants had apparently been hired by the restaurant in mid-Feb. to review its food safety management system following complaints from diners.

    The restaurant voluntarily closed Feb. 22, 2009, but didn’t bother telling health types until late Feb. 24 – and it was the consultants who notified investigators. By this time, 66 complaints of illness had been received by the restaurant, although no one had contacted the health department (because most people don’t know to contact the health department in suspected foodborne illness cases).

    Not telling health-types there is an outbreak going on and hoping it will go away reflects serious misgivings with upper – and the upperist – management.

    Abstract below.

    A large foodborne outbreak of norovirus in diners at a restaurant in England between January and February 2009
    Epidemiology and Infection 01.dec.11, FirstView Article : pp 1-7
    A. J. Smith, N. McCarthy, L. Saldana, C. Ihekweazu, K. McPhedran, G. K. Adak, M. Iturriza-Gomara, G. Bickler and É. O'Moore
    http://journals.cambridge.org/action/displayAbstract?fromPage=online&aid=8446062
    SUMMARY
    An outbreak of gastroenteritis affected at least 240 persons who had eaten at a gourmet restaurant over a period of 7 weeks in 2009 in England. Epidemiological, microbiological, and environmental studies were conducted. The case-control study demonstrated increased risk of illness in those who ate from a special ‘tasting menu’ and in particular an oyster, passion fruit jelly and lavender dish (odds ratio 7·0, 95% confidence interval 1·1–45·2). Ten diners and six staff members had laboratory-confirmed norovirus infection. Diners were infected with multiple norovirus strains belonging to genogroups I and II, a pattern characteristic of molluscan shellfish-associated outbreaks. The ongoing risk from dining at the restaurant may have been due to persistent contamination of the oyster supply alone or in combination with further spread via infected food handlers or the restaurant environment. Delayed notification of the outbreak to public health authorities may have contributed to outbreak size and duration.

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  • Posted: September 10th, 2011 - 6:09pm by Doug Powell

    The Monterey County Health Department is advising people to avoid consuming raw or undercooked oysters (such as those that are lightly steamed, marinated, or prepared as Rockefeller).

    Health types say several people reported illnesses associated with the naturally occurring bacterium Vibrio parahaemolyticu, which is most prevalent during summer months when water temperatures are most favorable for its growth.

    But local restaurants say their oysters are safe. Salinas Valley Fish House Owner Tony Digirolamo said he expects fewer people ordering oysters from his restaurant.

    "All people are going to hear is bad oysters so sure it's going to happen," says Digirolamo.

    "Our oysters are from the state of Washington and from colder waters," says Digirolamo. "That way they aren't that susceptible to a gulf oyster where the water is warmer."
    He also said, they keep tags on where their oysters are from, store them properly and buy them from reputable vendors. That's why Don Neilsen said he's not too concerned.

    "My feeling is as long you stick to a restaurant that gets its oysters from a reliable source, you should be all right," says Neilsen. "I don't intend to change my eating habits. I love oysters."

    For additional information on Vibrio parahaemolyticus:
    Centers for Disease Control - http://www.cdc.gov/nczved/divisions/dfbmd/diseases/vibriop/
    US Food and Drug Administration – Bad Bug Book - http://www.fda.gov/Food/FoodSafety/FoodborneIllness/FoodborneIllnessFoodbornePathogensNaturalToxins/BadBugBook/ucm070452.htm

     

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  • Posted: July 13th, 2011 - 7:11am by Doug Powell

    “A raw oyster can be like a petri dish.”

    So says Dr. Roger Danziger, a Bradenton (that’s in Florida) allergist, and why bacterial infections are why restaurant menus typically caution people against eating raw seafood.

    The Manatee County Health Department is investigating a local case of a bacterial infection contracted from eating oysters.

    Until the investigation is complete, the department is disclosing little about the case, including the possible source of the tainted oysters or even the date of the report.

    The department did identify the infection as stemming from the bacteria species Vibrio vulnificus.
     

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  • Posted: June 6th, 2011 - 9:34pm by Doug Powell

    There’s a whole bunch of folks who like to protect the reputation of raw oysters, and we’ve heard from them before.

    But it’s raw, and carries risks.

    Based on blog reports, the San Francisco Oysterfest last month featured raw oysters, beer and a lot of barf.

    "I am calling this event Salmonella-fest" wrote one yelper who, not surprisingly, gave the event just one star. Others wrote of suffering high fevers, shaking and even visiting the emergency room.

    The Department of Public Health was on the case -- and has determined the culprit was "campylobacter."

    Eileen Shields, spokeswoman for the health department, said investigators couldn't determine whether the bacteria was in the oysters, beer or any number of other food items served at the fest. After all, the food was all gone by the time word of food poisoning had gotten out.

    But rest assured, oyster lovers. Shields said there's no ongoing concern.

    Maybe San Fran should follow how close the human shit comes to oyster beds. Or how often food service employees wash their hands.
     

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  • Posted: June 30th, 2010 - 1:57pm by Doug Powell

    The Centre for Health Protection (CHP) of the Hong Kong Department of Health has received reports of 11 more people in food poisoning cases related to a restaurant in Jordan.

    As with the earlier clusters, they ate food from the restaurant on or before June 27.

    Stool specimens from six affected people in earlier clusters yielded positive result for Vibrio parahaemolyticus.

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  • Posted: March 25th, 2010 - 2:45am by Doug Powell

    The Louisiana state Department of Health and Hospitals has closed a large section of east bank Plaquemines Parish waters to oyster fishing through at least mid-April, after 11 people in Mississippi – at a seafood conference, repeat, at a seafood conference -- became sick after eating oysters believed to be traced to that area.

    The Times-Picayune reports the state has also issued a recall of any oysters harvested from that area since March 6, meaning wholesalers must review their records and contact any restaurants, brokers or other buyers who bought oysters from those waters. Under Food and Drug Administration and state health guidelines, oyster dealers are required to have a recall plan in effect.

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