Again, 11 sick: Blame the consumer Hong Kong edition

The Centre for Health Protection (CHP) of the Department of Health is today (January 19) investigating an outbreak of food poisoning affecting 11 persons, and reminded the public to maintain personal, food and environmental hygiene to prevent food-borne diseases.

The patients, comprising one man and 10 women aged 63 to 76, developed abdominal pain, nausea, vomiting, diarrhoea and fever about 12 to 26 hours after having lunch at a restaurant at Lau Fau Shan in Yuen Long on January 7.

Five of them sought medical attention, of whom one required hospitalisation but was discharged upon treatment. The stool specimen of that patient tested positive for Vibrio parahaemolyticus. All affected persons are now in stable condition.

‘Something will always be somebody’s last meal’ Does it have to be today?

My favorite food safety fairytale is along the lines of, we’ve always produced food this way and no one has ever gotten sick.

Because bugs don’t change, food don’t change, people don’t change.

Raw oysters, the renowned aphrodhsiac, is especially prone to fairytale hyperbole.

Delayna Earley of the Island Packet in South Carolina, writes, who doesn’t love a good oyster roast?

“I’ve been doing this all my life and we’ve never had a case of anyone dying from eating an oyster,” Larry Toomer, owner of the Bluffton Oyster Co., said. “We know where our oysters came from because we harvest them, refrigerate them ourselves and then cook them shortly after.”

Toomer says that there is always a risk when consuming any raw food, but the oysters that are harvested off the coast of the Low country typically don’t have bacteria due cleansing nature of the tidal waters they grow in.

“Something will always be somebody’s last meal,” Toomer says. “If you’re immune system is not up to snuff you shouldn’t eat anything raw, whether that is an oyster, or burger or any other type of meat, but something is going to set you off if you’re already sick. But other than that, we shouldn’t worry too much.”

Raw is risky: Oysters strike down victims in Louisiana, Hong Kong

A Texas woman who spent a day along the Louisiana coast crabbing with friends and enjoying oysters found herself fighting for her life just 36 hours later, KLFY-TV reported.

Jeanette LeBlanc contracted a deadly flesh-eating bacteria called Vibrio that day, resulting in her death a few weeks later.

LeBlanc’s symptoms started out similar to an allergic reaction. In fact, that’s what she suspected it was before doctors told her otherwise. She had red patches of a rash on her legs and experienced respiratory issues before the symptoms worsened, KLFY reported.

The Centers for Disease Control and Prevention said the bacteria that causes Vibriosis creates 80,000 cases of illness in the United States each year and 100 deaths. The Vibrio bacteria live in coastal waters, those where oysters also live. The oysters contract the bacteria by filtering water to feed and the bacteria ends up in the tissues of the oyster, then when someone like LeBlanc eats it raw, they also contract the bacteria.

In Hong Kong, the Centre for Health Protection (CHP) of the Department of Health today (December 29) reported its investigations into three food poisoning outbreaks suspected to be related to the consumption of raw oysters in three different restaurants.

They involve:

  1. One man and two women, aged from 25 to 39, who have developed abdominal pain, diarrhea and vomiting about 11 to 50 hours after having lunch (including raw oysters) in a restaurant in Yau Ma Tei on December 17. All sought medical attention;

2.Two women, aged from 36 to 37, who have developed similar symptoms about 30 to 33 hours after having dinner (including raw oysters) in a restaurant in Kowloon Bay on December 19. Both sought medical attention; and

  1. One man and three women, aged from 22 to 24, who have developed similar symptoms about 16 to 59 hours after having dinner (including raw oysters) in a restaurant in Tsim Sha Tsui on December 25.

One sought medical attention.

Raw is risky: Norovirus in raw oysters sickens 10 in Denmark

Joseph James Whitworth of Food Quality News writes 10 people have been sickened by norovirus after eating raw oysters at Danish restaurants.

Fødevarestyrelsen (Danish Veterinary and Food Administration) said oysters are from Lemvig.

The agency has closed the area in Lemvig for commercial harvest of mussels and oysters and is monitoring it.

Illnesses can be avoided if oysters are cooked to an internal temperature of 90° Celsius/194° Fahrenheit for a minimum of 90 seconds.

Raw is risky: 25 sickened by oysters in Seattle

A foodborne illness outbreak linked to raw oysters has sickened at least 25 people who dined at local restaurants recently, King County reported on Tuesday. The news comes after the county reported last week that a handful of people got sick eating raw oysters at two Seattle restaurants – The Salted Sea and The White Swan Public House.

The restaurants, however, are not the source of the outbreak, King County says. Most likely, the oysters were mishandled or contaminated before reaching local restaurants, although no specific local oyster beds have been connected to the outbreak.

County health officials believe diners have been sickened by Vibrio, a marine bacteria commonly found in oysters.

“Eating undercooked or raw shellfish, especially raw oysters in warm-weather months, is the main risk for acquiring vibriosis from infection with Vibrio parahaemolyticus,” King County said.

I’m not your guy, pal: Raw oysters risky for wine drinkers

When Canada’s food safety agency announced a recall of B.C. oysters last August, it meant producers like Steve Pocock had to ensure every last oyster they had shipped after a certain date was accounted for.

Oyster-Vancouver, B.C.- 07/05/07- Joe Fortes Oyster Specialist Oyster Bob Skinner samples a Fanny Bay oyster at the restuarant. Vancouver Coastal Health now requires restaurants to inform their patrons of the dangers of eating raw shellfish.  (Richard Lam/Vancouver Sun)   [PNG Merlin Archive]

Along with a recall – issued by the Canadian Food Inspection Agency (CFIA) after dozens of people got sick as a result of eating raw oysters contaminated with Vibrio parahaemolyticus – there was a ban on restaurants serving raw oysters from British Columbia.

The inconvenience and forgone sales added up to a big hit for Mr. Pocock and other producers in British Columbia’s oyster sector.

Over the past few months, they have been working to prevent a repeat scenario.

“The recall had a very serious impact on our industry – and it should be taken very seriously,” Mr. Pocock said in a recent interview. He owns and operates Sawmill Bay Shellfish and is also president of the BC Shellfish Grower’s Association.

“And I’m not just talking about the farmers; I’m talking about everyone right through to the server in the restaurant,” he added.

A workshop last November spawned a national working group focused on Vibrio with representatives from the Canadian Food Inspection Agency, Fisheries and Oceans Canada, Health Canada, the BC Centre for Disease Control (BCCDC) and provincial health authorities.

That group developed a prevention program for Vibrio, focusing on education, enhanced testing and improved communication between producers and government agencies.

On the education front, workshops for producers emphasized measures to control Vibrio, such as proper refrigeration during transport.

Oysters represent a relatively small chunk of British Columbia’s aquaculture sales – $13-million, compared with $380.4-million for salmon, according to a 2015 report by British Columbia’s Ministry of Agriculture – but are prized for their taste and local appeal.

“Shellfish are an important part of our business, and especially in the summertime, when patios are open, [oysters] go great with wine and it was disappointing we were unable to offer B.C. product for raw consumption,” said Guy Dean, vice-president of seafood distributor Albion Fisheries.

Yeah, especially since Vibrio produces a toxin that attacks the weak livers of persistent wine drinkers.

Raw is risky.

And this Guy ain’t your buddy. Or friend.

I don’t eat raw oysters: Gross and may have Vibrio

Following up a scientific report, Timothy B. Wheeler of the Bay Journal reports a 6-year-old outbreak of food poisoning linked to eating raw Chesapeake Bay oysters has left behind a lingering mystery. Scientists seeking to identify the water-borne pathogen that sickened a pair of Baltimore restaurant patrons have tracked the culprit to Asia.

Raw oystersHow a potent strain of Vibrio bacteria seemingly from so far away wound up in the Bay continues to puzzle Maryland health officials, who worked with researchers at the U.S. Food and Drug Administration to investigate the 2010 cases.

The microorganism could have gotten here in the ballast water of the many oceangoing ships that ply the Chesapeake every year, state and federal scientists suggested in a recently published journal article. Or, they added, perhaps it came via the introduction of non-native oysters or some exotic fish.

“It really is speculation,” acknowledged Dr. Clifford Mitchell, environmental health bureau director for the Maryland Department of Health and Mental Hygiene. “We didn’t sample ballast water. We didn’t take specimens that would lead us to know that we had fish coming over, or migration.”

But the case, published in the June issue of Applied and Environmental Microbiology, illustrates how disease-carrying organisms may travel around the world, researchers said. And while steps have been taken since 2010 to prevent the unintentional transport of pathogens, parasites and other potentially harmful organisms via ships’ ballast water, those safeguards still have significant gaps in them.

The bacterium involved in the 2010 food poisoning outbreak was Vibrio parahaemolyticus, strains of which are commonly found in coastal waters worldwide — including the Bay — though only some have been found to cause illness. When those are ingested, they can cause acute gastrointestinal distress, including diarrhea, stomach pain, nausea, fever and chills. It usually passes within a few days, but in rare cases can be more severe, especially in people with weakened immune systems.

There were 45 cases of Vibrio infections reported in Maryland in 2010, but it’s not that often, state health officials said, that they’re able to pinpoint the source of the bacteria that may have sickened a particular person. By the time laboratory tests identify Vibrio as the cause of someone’s GI distress and the information gets reported to the state, days or even weeks may have passed, and the food that person had eaten is long gone.

In this case, though, state health investigators got a lucky break. Two individuals who got sick said that shortly before they became ill that summer, they had eaten raw oysters at different Baltimore restaurants. They hadn’t traveled out of state or done anything else that likely could have exposed them.

When investigators visited the restaurants, they found the half-shells eaten by the two victims were from the Bay. And when they visited the Maryland aquaculture operation that supplied both eateries, investigators pulled some oysters from the water and discovered that they had Vibrio in them as well — 11 different potentially disease-causing strains, in fact. One of those appeared to match the Asian strain found in the two food poisoning victims.

Coos Bay Oyster Co.The investigation ended there, for the time being. Even though the Vibrio involved were similar, researchers couldn’t positively identify them as the same, using the analytic techniques they had at the time. “The chromosome patterns matched, but we weren’t sure how common that pattern was in the environment,” explained Robert Myers, director of the state health department’s laboratory administration. “We hadn’t seen it before.”

A few years later, though, “whole genome sequencing” technology became available, Myers said, giving researchers the ability to draw a more detailed map of an organism’s genetic makeup.

With that new, more powerful analytical tool, FDA researchers re-examined the Vibrio strains involved in the 2010 outbreak and those from the oysters that state health investigators had sampled. They identified them as belonging to a family of strains known as “sequence type 8.” 

When researchers consulted a worldwide Vibrio database, they found that the Maryland strains were unlike any seen to date in the United States. Instead, they were closely related to strains reported only in Asia, most recently in Hong Kong about four years before the outbreak.

Changes were made to shellfish safety protocols after a larger outbreak in 2013of Vibrio parahaemolyticus illnesses associated with eating raw oysters harvested along the Atlantic Coast. More than 100 people in 13 states, including Maryland and Virginia, became ill.  According to a spokesman for the Maryland Department of the Environment, which regulates shellfish harvest waters in the state, the Interstate Shellfish Sanitation Conference, a joint state-federal body, tightened its requirements for investigating such cases, closing implicated harvest areas and ordering a product recall when more than 10 cases are traced to a given area. 

But officials caution that the protocols are not foolproof, and cases like this are a reminder of the risk people run in consuming raw seafood, Mitchell said, especially if they have underlying health conditions.

The number of reported Vibrio infections in the state varies from year to year, but has been trending upward since 2005, according to state health data. Concentrations of the bacteria increase in warmer weather, and climate change could be a factor as Bay water temperatures tick upward. But Mitchell cautioned that the bacteria are present year-round.

“Given the number of people who eat oysters, certainly it’s a relatively small number of infections, but it can be a very significant one,” Mitchell said.

3 sick from Norovirus in raw oysters in Hong Kong

The Centre for Health Protection (CHP) of the Department of Health is today (January 12) investigating a food poisoning outbreak and reminds the public to maintain personal, food and environmental hygiene to prevent food-borne diseases.

Raw oystersThe outbreak has affected three women, all aged 27. They developed vomiting, abdominal pain, diarrhoea and fever about 24 to 40 hours after having dinner in a food premises in Quarry Bay in the evening of January 3. The trio then sought medical attention and no hospitalization was required.

They have remained in stable condition.

The stool specimen of one of them tested positive for norovirus upon laboratory testing by the hospital. The CHP’s initial enquiries revealed that the trio had consumed raw oysters.

Raw is risky: I only eat cooked oysters (and didn’t get any for our 7 fishes feast tonight)

Although Salmonella has been isolated from 7.4 to 8.6% of domestic raw oysters, representing a significant risk for food-borne illness, little is known about the factors that influence their initial colonization by Salmonella.

oysters.grillThis study tested the hypothesis that specific regulatory changes enable a portion of the invadingSalmonella population to colonize oysters.

An in vivo promoter probe library screen identified 19 unique regions as regulated during colonization. The mutants in the nearest corresponding downstream genes were tested for colonization defects in oysters. Only one mutation, in ssrB, resulted in a significantly reduced ability to colonize oysters compared to that of wild-type Salmonella. Because ssrBregulates Salmonella pathogenicity island 2 (SPI-2)-dependent infections in vertebrate macrophages, the possibility that ssrB mediated colonization of oyster hemocytes in a similar manner was examined. However, no difference in hemocyte colonization was observed.

The complementary hypothesis that signal exchange between Salmonella and the oyster’s native microbial community aids colonization was also tested. Signals that triggered responses in quorum sensing (QS) reporters were shown to be produced by oyster-associated bacteria and present in oyster tissue. However, no evidence for signal exchange was observed in vivo.

The sdiAreporter responded to salinity, suggesting that SdiA may also have a role in environmental sensing. Overall, this study suggests the initial colonization of live oysters by Salmonella is controlled by a limited number of regulators, includingssrB.

 Influence of Salmonella enterica Serovar Typhimurium ssrB on colonization of eastern oysters (Crassostrea virginica) as revealed by a promoter probe screen

Appl. Environ. Microbiol. January 2016 82:328-339; Accepted manuscript
posted online 23 October 2015, doi:10.1128/AEM.02870-15

Clayton E. Cox, Anita C. Wright, Michael McClelland, and Max Teplitski

http://aem.asm.org/content/82/1/328.abstract?etoc