Microbiologists: Avoid raw oysters

Oysters not only transmit human norovirus; they also serve as a major reservoir for these pathogens, according to research published August 28 in Applied and Environmental Microbiology, a journal of the American Society for Microbiology. “

steamed.oystersMore than 80 percent of human norovirus genotypes were detected in oyster samples or oyster-related outbreaks,” said corresponding author Yongjie Wang, PhD.

“The results highlight oysters’ important role in the persistence of norovirus in the environment, and its transmission to humans, and they demonstrate the need for surveillance of human norovirus in oyster samples,” said Wang, who is Professor in the College of Food Science and Technology, Shanghai Ocean University, Shanghai, China.

In the study, the investigators downloaded all oyster-related norovirus sequences deposited during 1983-2014 into the National Center for Biotechnology’s GenBank database, and into the Noronet outbreak database. They conducted genotyping and phylogenic analyses, and mapped the norovirus’s genetic diversity and geographic distribution over time.

In earlier research, the investigators found that 90 percent of human norovirus sequences in China came from coastal regions. The current research showed that the same is true all over the world, except in tropical regions, from which sequences are absent.

Oysters’s status as reservoirs and vectors for human norovirus transmission is likely abetted by their presence in coastal waters, which are frequently contaminated by human waste, said Wang. Previous research suggests that noroviruses can persist for weeks in oyster tissues, and commercial depuration fails to expunge them.

Norovirus causes stomach pain, diarrhea, nausea, and vomiting. It is extremely contagious, and infects more than 6 percent of the US population, annually, resulting in around 20 million cases, including 56,000-71,000 hospitalizations and 570-800 deaths, according to the Centers for Disease Control and Prevention. Even touching a contaminated surface can result in infection.

Wang advised that people who eat oysters and other shellfish should eat them fully cooked, and never raw. He also urged development of a reliable method for detecting noroviruses in oysters, and a worldwide oyster-related norovirus outbreak surveillance network.

Lemon juice and human norovirus

Brisbane is equidistant from the equator as Sarasota, Florida, and we have fabulous citrus.

lemon.lime.bittersLemon-lime-and-bitters has become my go-to drink, along with the bubbly water provided by our soda stream.

But will lemon juice reduce my risk of contracting Norovirus?

Maybe.

Researchers at the German Cancer Research Center say that lemon juice could be a potentially safe and practical disinfectant against Norovirus.

I wouldn’t rely on it.

Human noroviruses does not grow in cell culture, so they tested the effects of increasing concentrations of citric buffer on the so called norovirus virus-like particles, which have the same surface characteristics as real viruses. Dr Grant Hansman, head of CHS junior research group at the German Cancer Research Center noroviruses and the University of Heidelberg and his staff show that the virus particles change their shape after citrate binding. X-ray crystal structures revealed that the citrate – from lemon juice or citrate disinfectants – precisely interacts at the binding pocket on the particle that is involved in attaching to host ligands – the so-called histo-blood group antigens.

These new results may explain why citrate reduces the infectivity of noroviruses. “Maybe a few drops of lemon juice on contaminated food or surfaces may prevent the transmission of these viruses,” speculates Hansman. With his staff, he now plans to investigate if citric acid could reduce symptoms in those already infected with noroviruses.

That’s a lot of maybes.

Anna D. Koromyslova, Peter White, and Grant S. Hansman: Citrate alters norovirus particle morphology. Virology 2015, DOI: 10.1016/j.virol.2015.07.009

Heston-norvirus-isn’t-my-fault Blumenthal reopens his Fat Duck restaurant

The Daily Mail delivers what those in the biz call a BJ-piece in a fawning portrait of Heston Blumenthal, whose new menu will take diners on a ‘story-telling’ journey aimed at capturing childhood feelings of adventure when the new menu at his Fat Duck restaurant launches next month.

heston.blumenthalI have those childhood memories: being on the couch for a couple of days, watching bad game shows and barfing endlessly, much like the 529 diners and staff who were sickened by norovirus at the Fat Duck in 2009.

He has even turned to magician Derren Brown for tips on how to personalise people’s dinner choices by using auto-suggestion techniques so that diners get what they think they most crave.

Get the food safety right first, then indulge yourself with magic.

He also acknowledged that having more than 70 staff make handmade food for 40 seats at each service would likely force up the price of a meal.

Follow the money.

The vomit machine, not just for parties; useful for modeling norovirus

I’ve been lucky to be close to some excellent projects, some of the stuff and knowledge created through these projects ends up mattering to food safety nerds – especially those who are making risk management decisions. NC State student Grace Tung-Thompson’s PhD project on vomit spray and norovirus is one of the most impactful. The work was carried out as part of the USDA NIFA-funded NoroCORE project led by my friend Lee-Ann Jaykus.VOMIT-BLOG-HEADER-698x393

I’ve talked to lots of Environmental Health Specialists, retailers and food service food safety folks about what Grace and fellow graduate student Dominic Libera put together and many respond with a weird level of enthusiasm for the barf project.

Mainly because a real question they struggle with is how far will virus particles travel from an up-chuck event – knowing this, and then cleaning and sanitizing helps limit the scope of a potential outbreak. Today Grace’s work was published in PLOS ONE.

Matt Shipman, Research Communications Lead for University Communications and all around great guy writes about the project for The Abstract:

Tucked away in a quiet lab on NC State’s Raleigh campus is something that looks like a glorified air compressor with a grotesque clay face. It’s called “the vomiting machine” and it does exactly what you think it does. Researchers are using it to study one of the most widespread pathogens in the United States: norovirus.

Norovirus is a group of more than 30 related viruses that can cause vomiting and diarrhea. Norovirus affects about 20 million people each year in the U.S., with infections that can lead to hospitalization and occasionally to death, particularly in the elderly. About a quarter of the time, “noro” infection is obtained by consuming contaminated foods or water.  However, it is most often spread between people in close contact with each other.  The epidemic GII.4 strain predominates, but there are others.

But how, exactly, is noro transmitted from person to person?

“Epidemiological studies have suggested that norovirus can be ‘aerosolized’ through vomiting, meaning that small particles containing norovirus can become airborne when someone throws up,” says Grace Thompson, a recent Ph.D. graduate whose work at NC State focused on how norovirus spreads through vomiting and how long it is detectable in vomit. (Fun fact: noro can still be detected in dried vomit after six weeks.)

“According to outbreak reports, it appears that people can become infected with noro if they are directly or indirectly exposed to vomiting events,” Thompson explains. “If aerosolized particles land on a countertop, you could also touch the counter with your hand, then touch your hand to your mouth, leading to infection.”

But while norovirus aerosolization by vomiting has long been suspected, no one knew if it was actually occurring. This is the sort of question that Lee-Ann Jaykus’s lab lives for.

Jaykus is a professor of food science at NC State and scientific director of the U.S. Department of Agriculture-National Institute of Food and Agriculture Food Virology Collaborative, also known as NoroCORE (short for Norovirus Collaborative for Outreach, Research, and Education). They are, quite simply, norovirus experts.

To see if vomiting could really aerosolize norovirus, researchers in Jaykus’s lab (including Grace Thompson) needed a controlled way to observe and study vomiting over and over again. They needed a vomiting machine.

As you may imagine, there is a limited demand for vomiting machines, so the researchers had to design and build their own. They found a partner in Dominic Libera, a graduate student in NC State’s civil, construction and environmental engineering department in Francis de los Reyes’s lab.  They also needed data upon which to build their model.  Dr. Kenneth Koch, a gastroenterologist with Wake Forest University, provided that expertise.

Working together, the researchers created a machine that is essentially a scaled-down version of the mouth, esophagus, and stomach – made of tubes and a pressure chamber that passes through a clay face to give it the correct vomiting angle. The machine is designed (using engineering similitude principles) to let researchers control the pressure and volume of the vomit, in order to mimic a range of natural vomiting behaviors. The whole thing is enclosed in a sealed plexiglas box and placed under a biosafety hood. (A short video of the machine can be seen here.)

Instead of vomit, the researchers use liquid solutions of different viscosities or thicknesses as “artificial vomitus” to reflect different stages of digestion. And, since they cannot use real norovirus, they used a bacteriophage called MS2, which is a virus that infects E. coli but is harmless to humans. MS2 is easy to culture and is a common stand-in for noro.

Putting The Machine To Work

In 2012 and 2013, the team did extensive testing of the machine, to make sure that it was scaled appropriately and worked the way they wanted it to. And in 2014, Thompson began using the machine for formal experiments.

And what did they find? Well, virus was indeed aerosolized.  Although the amount of MS2 aerosolized as a percent of total virus “vomited” was relatively low (less than 0.3 percent), vomit from infected people contains millions of particles. When the math is done, this means that the actual amount of virus particles aerosolized during a single vomiting event ranges from only a few into the thousands, perhaps more. (This work was recently published in PLOS ONE. More information on the findings is available here.)

“And that is enough to be problematic because it only takes a few, perhaps less than 20, to make a susceptible person ill” Jaykus says. “This machine may seem odd, but it’s helping us understand a disease that affects millions of people. This is work that can help us prevent or contain the spread of norovirus – and there’s nothing odd about that.”

Bad idea: Raw oysters in nursing homes

With at least 67 sick from Vibrio parahaemolyticus linked to raw oysters in Canada and a full recall being launched by the Canadian Food Inspection Agency, one has to wonder why raw oysters would be served in a nursing home.

oystersBut that’s what happened in France in 2012.

Researchers report that the presence of norovirus in shellfish is a public health concern in Europe. Here, we report the results of an investigation into a norovirus gastroenteritis outbreak following a festive lunch which affected 84 (57%) residents and staff members of a nursing home in January 2012 in France. Individuals who had eaten oysters had a significantly higher risk of developing symptoms in the following 2·5 days than those who had not, the risk increasing with the amount eaten [relative risk 2·2 (1·0–4·6) and 3·3 (1·6–6·6) for 3–4 and 5–12 oysters, respectively].

In healthy individuals during those days, 29 (32%) subsequently became ill, most of whom were staff members performing activities in close contact with residents. Genogroup II noroviruses were detected in fecal samples, in a sample of uneaten oysters and in oysters from the production area. Identifying a norovirus’s infectious dose may facilitate the health-related management of contaminated shellfish.

A norovirus oyster-related outbreak in a nursing home in France, January 2012

Epidemiology and Infection / Volume 143 / Issue 12 / September 2015, pp 2486-2493

Loury, F. S. Le Guyader, J. C. Le Saux, K. Ambert-Balay, P. Parrot and B. Hubert

http://journals.cambridge.org/action/displayAbstract?fromPage=online&aid=9888431&utm_source=Issue_Alert&utm_medium=RSS&utm_campaign=HYG

Calling all norovirus: passenger forced to sit beside vomit on plane

I’ve encountered vomit in public a few times.

A few weeks ago a fellow food safety nerd and I sat on a Seattle train and watched a woman 20 ft away yack on the floor while her partner consoled her. My friend and I figured that we’d get noro just by being there (we didn’t).CMhGalfWUAAnNds

A few years ago my son threw up on a flight which led to a fascinating approach by Delta Airlines involving plastic bags to contain the risk and coffee pods to manage the smell.

According to BBC, a Rynair passenger was forced to sit next to a vomit pile on a flight from Gatwick to London this week.

A 24-year-old was forced to sit in the same aisle as vomit left by a previous passenger on a Ryanair flight from Gatwick to Dublin on Sunday.

Noel O’Hare noticed the smell and mess as soon as he sat down with his friends on the hour and a half flight.220px-Neilyounglandingonwatercover

He told Newsbeat the “unsightly mess” was on the ground mixed in with a bag and tissues.

Ryanair cabin staff told him that because Gatwick isn’t their base and their cleaners are in Dublin, it couldn’t be cleaned up until they arrived back in Ireland.

Spray and aerosolization of vomit particles makes being in that adjacent seat particularly fun.

My frozen berries are now all boiled for a minute, linked to thousands of sickness in EU over past decade

Frozen berries have been linked to 26 cases of food contamination in the European Union in the past nine years.

frozen.strawberryHepatitis A, norovirus (a type of viral gastroenteritis) and Shigella sonnei (a type of dysentery) infections were identified as the main threat from the berries.

That’s according to a review released last week, which showed there had been 32 independent outbreaks of disease caused by contaminated frozen berries in the EU between 1983 and 2013, with more than 15,000 cases of norovirus reported.

It comes after Australian food processor Patties Foods recalled some of its frozen berries — which it imports from China — when 34 cases of Hepatitis A were linked to the products in February.

The Weekly Times revealed in March Australia had suffered dozens of its own food safety scandals in the past decade — mostly linked to contaminated fruit.

Blame consumers: How to handle an egg edition

Less than half of adults, only 48 percent, wash their hands with soap and water after cracking eggs, and over 25 percent eat cookie dough or cake batter containing raw eggs, according to a study published last month in the Journal of Food Protection. Both activities put a person at serious risk for food poisoning.

raw.egg.mayo“It’s shocking,” says lead author Katherine Kosa, a research analyst in food and nutrition policy at RTI International, a nonprofit research organization based in North Carolina. In an earlier study, her team found that 98 percent of people wash their hands after handling raw poultry, but somehow that same logic hasn’t extended to eggs, she says.

She and collaborators surveyed 1,504 US grocery shoppers about their food-handling habits. The researchers were happy to find that 99 percent of people purchased refrigerated eggs and kept them refrigerated. Keeping eggs adequately cool prevents any salmonella present in the eggs from growing to dangerous levels.

What goes in the fridge for safety reasons and other tales

Evidence and perception aren’t often congruent in the food safety world. There are lots of examples from the pages of the Internet: Dirty bathrooms are an indicator of sanitation in the kitchen; pathogens won’t transfer in less than five seconds when food hits the floor; and, yogurt is dangerous if consumed after the best-before date are just a few.

K. Aleisha Fetters of Yahoo News connected with Schaffner and I on the difference between refrigeration for safety and keeping stuff cool for spoilage and quality reasons.

Here are some excerpts.k2-_bd216f83-0923-407e-aea5-f57dc7338ebc.v1

Ketchup: Can remain at room temperature.
Ever wondered why restaurants keep ketchup on their tables rather than back in the fridge? Because it won’t make you sick, says Benjamin Chapman, PhD, associate professor and food safety extension specialist at North Carolina State University. Ketchup is so acidic that it prevents the growth of harmful bacteria. It will spoil faster if left out on the counter, but it could still take months to turn bad.

Fruits and vegetables: It depends.
If you think about it, fruits and vegetables grow outside at temps far higher than room temperature. That’s why, when they are whole, they are safe on your counter. However, when you cut them (or in the case of lettuce, just tear their stems from the ground), you actually rip open the cells of the plant. This releases nutrients, water, and bacteria, and allows them to mingle with each other, says food microbiologist Donald W. Schaffner, PhD, distinguished professor at Rutgers University. For example, when you cut a tomato or avocado, you need to keep it in the fridge to prevent the growth of salmonella. However, it’s worth noting that listeria can grow (albeit slowly) at cold temps. That’s why, even if you keep cut melons in the fridge, you should throw them out or add them to the compost pile after four days, Chapman says.

Mayonnaise: Must be refrigerated.
Well, this one is really more of an “it depends,” but we’re going to suggest sticking it in the fridge just in case. Most store-bought mayo is acidic enough to keep on the counter without it growing bad-for-you bacteria all by itself. (That’s why fast-food joints can keep it out in pumps until it’s used up.) But, if you cut some veggies with a knife, and then stick that knife in your jar of mayonnaise, you could potentially introduce bacteria into the mayo that is able to grow at room temperature, Chapman says. Meanwhile, whatever the recipe, homemade mayo is generally not acidic enough to fend off pathogens.

No more handshaking on Crystal Cruises to limit norovirus

Fist bumps and finger guns rule the Captain’s greeting line on Crystal Cruises. The luxury line is, according  to ABC News, employing a no handshake policy to keep norovirus at bay.

Crystal Cruises has a no-shake rule for the captain, in addition to other “preventative measures” when it comes to health and safety on board its ships.

 “The safety and health of our guests and crew is paramount at Crystal Cruises. We maintain exemplary sanitation standards and facilitate preventive measures in accordance with Centers for Disease Control recommendations, including thorough disinfection of public areas, and high-touch surfaces like railings, door handles and elevator buttons,” the cruise line said in a statement to ABC News. 

“Other measures involve encouraging guests to use the complimentary anti-bacterial wipes before boarding the ship. And while the captain is very pleased to meet all our guests, he refrains from shaking hands as an additional preventive measure.”

I’d want to see data on the antibacterial wipes efficacy against human norovirus before employing them as a control measure.