Yearly Archives: 2015

Placental breach mechanism for Listeria revealed

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The host blood-brain and placental barriers act as critical ramparts to infections from microbial pathogens, yet some have evolved mechanisms to breach the cellular obstacles that lie in their path. Unlocking the underlying mechanisms of host barrier permissiveness to microbes is critical to understanding the etiology of many infectious diseases.

amy.pregnant.listeriaThe common foodborne bacteria Listeria monocytogenes (Lm) can survive and proliferate within the intestinal lumen of the host, which then often progresses to the bacteria traversing the blood-brain barrier, causing meningitis and encephalitis, as well as the placental barrier, resulting in severe neonatal infection or miscarriage.

Researchers at the Pasteur Institute in Paris have discovered the protein pathways that are responsible for allowing Listeria to circumvent host barriers. The results from this study were published today in the Journal of Experimental Medicine within an article entitled “PI3-kinase activation is critical for host barrier permissiveness to Listeria monocytogenes”.

Listeria relies on two surface proteins called internalins, InlA and InlB, to guide them across mucosal tissue barriers. These proteins bind to receptors on the surface of host cells and are required for the bacteria to traverse the placenta, but InlA alone can thrust it across the intestine. The underlying difference between InlA and InlB is still being investigated. 

The scientists discovered that the invasion process was dependent upon the enzymatic activity of the host cell phosphoinositide 3-kinase (PI3K) pathway. Marc Lecuit, M.D., Ph.D., Head of the Biology of Infections Unit at the Pasteur Institute and senior author on the study, and his colleagues found that although PI3K is turned on by both of Listeria’s internalins, only InlB has an inherent mechanism for flipping the switch. 

“We show that Lm intestinal target cells exhibit a constitutive PI3-K activity, rendering InlB dispensable for InlA-dependent Lm intestinal barrier crossing. In contrast, the placental barrier does not exhibit constitutive PI3-K activity, making InlB necessary for InlA-dependent Lm placental invasion,” the paper noted.

jaucelynn.pregnantSince many organisms share evolutionarily conserved mechanisms for successful survival and proliferation, these findings may offer  much needed insight into how other pathogenic organisms are able to take up pervasive residence inside host tissues.    

“These results illustrate how microbial pathogens have evolved to invade mammalian tissues, taking advantage of both similarities and differences of host barriers. They also suggest that the absence of placental constitutive PI3-K activity may reinforce its barrier function toward pathogens, with the exception of those that have evolved ways to stimulate it exogenously, like Lm,” the authors concluded.

Which cut of meat is least likely to make you sick?

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I like Schaffner’s response: There is no such thing as risk-free meat, or risk-free food in general. Donald Schaffner, a professor of food microbiology at Rutgers University, told Kiera Butler of Mother Jones that if the food isn’t cooked sufficiently, or if the preparation area isn’t clean, it doesn’t matter whether you’re eating chicken, steak, or pork,” he says. “Food prepared in an unclean environment is always going to be high risk.”

GrilledSteak-main_FullI told her that requesting your meat “well done” or “medium” won’t save you from illness, either. Those terms are vague and subjective, says Doug Powell, a former professor of food safety and current publisher of the foodborne illness site barfblog.com “When I go to a restaurant and they ask me how I want my steak, I say ‘140 degrees,'” he says. “If they give me a funny look I get up and leave.”

Butler writes that every time you eat, you’re rolling the germ dice.

But some cuts are more likely to make you sick. In 2013, researchers from the Center for Science in the Public Interest (CSPI) analyzed data about outbreaks, illnesses, and hospitalizations from foodborne pathogens in particular kinds of meat between 1998 and 2010.

Contaminated chicken sickens more people than any other meat. That’s partially because we eat so much of it—more than 50 pounds a year per person. But it’s also because of the way that chicken is prepared and cooked, says Caroline Smith DeWaal, CSPI’s director of food safety. Commercial chicken plants typically dip the meat in several baths before packaging, giving bacteria plenty of opportunity to spread. What’s more, says Smith DeWaal, it’s harder to cook away bacteria in chicken. “Chicken has creases and folds in the skin,” she says. “Pathogens can hide in those folds. A lot of other meat doesn’t even come with skin on.”

Ground beef is the second riskiest kind of meat. One reason for this, says Smith DeWaal, is that during grinding, “the pathogens on the surface of the meat get pushed into the center.” If that ground meat isn’t properly cooked—say, in the middle of a rare burger—the germs get a free ride into your digestive tract.

rowan.atkinson.steak.tartareSteaks, pork chops, and other whole-muscle meats are the safest bet. That’s because the cooking process can easily kill off bacteria on the cut’s surface, while the inside of the meat is essentially sterile, protected from any potential pathogens—in theory.

But steak isn’t as safe as it should be. According to the US Food Safety and Inspection Service, about 10.5 percent of steaks are subjected to a process called mechanical or needle tenderization, where metal blades or pins repeatedly puncture the meat before packaging. While this technique improves the meat’s texture, it also moves bacteria from the surface into the center of the cut, where the germs may survive cooking. The scary part: Processors are not required to label cuts that have been mechanically tenderized—so there’s no way to know whether your steak might have extra interior bacteria. Mechanically tenderized beef has caused several recent outbreaks, including one in Canada in 2012, which sickened 18 people and led to the biggest beef recall in Canadian history. In 2013, the US Department of Agriculture promised to require labeling on mechanically tenderized beef, but the agency is stalling on finalizing that rule.

115 sickened: Multistate outbreak of Salmonella Enteritidis infections linked to bean sprouts (Final update)

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The U.S. Centers for Disease Control reports this outbreak appears to be over.

wonton.foodA total of 115 people infected with the outbreak strains of Salmonella Enteritidis were reported from 12 states.

Twenty-five percent of ill persons were hospitalized. No deaths were reported.  

Collaborative investigation efforts of state, local, and federal public health and regulatory agencies indicated that bean sprouts produced by Wonton Foods, Inc. were the likely source of this outbreak.

In interviews, 61 (72%) of 85 ill persons reported eating bean sprouts or menu items containing bean sprouts in the week before becoming ill.

In November 2014, Wonton Foods Inc. agreed to destroy any remaining products while they conducted a thorough cleaning and sanitization and implemented other Salmonella control measures at their firm. The firm resumed shipment of bean sprouts on November 29, 2014.

Contaminated bean sprouts produced by Wonton Foods, Inc. are likely no longer available for purchase or consumption given the maximum 12-day shelf life of mung bean sprouts.

sprouts.kevinAlthough this outbreak appears to be over, sprouts are a known source of foodborne illness. CDC recommends that consumers, restaurants, and other retailers always follow food safety practices to avoid illness from eating sprouts.

Be aware that children, older adults, pregnant women, and persons with weakened immune systems should avoid eating raw sprouts of any kind (including alfalfa, clover, radish, and mung bean sprouts).

We count 61 outbreaks associated with raw sprouts, sickening at least 11,179.

https://barfblog.com/wp-content/uploads/2014/12/Sprout-associated-outbreaks-12-8-14.xlsx

I’m all for food hubs but food safety needs to be on the menu

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As Ashley Chaifetz, public policy student at UNC-Chapel Hill wraps up her research on food pantries her data shows really passionate individuals (largely volunteer) who work within a food distribution system that’s not all that systematic or formal when it comes to food safety training. Kind of like the emerging world of food hubs.

The hippie, punk rock, F the man part of me loves the idea of grassroots, community-led food hubs – but my public health conscience leads me to believe that microbial food safety has to be part of the passion or hubs are doomed to fail at the first outbreak.03-25-10-food-hub

Laurie Davis, of Cornell Cooperative extension explains what food hubs are in the Press Republican:

Just what is a food hub?

The U.S. Department of Agriculture defines it as “a centrally located facility with a business management structure facilitating the aggregation, storage, processing, distribution, and/or marketing of locally/regionally produced food products.” This is a broad definition because a food hub can assume many different forms.

It might just be a building where local food is delivered, temporarily stored, then shipped back out, or longer term storage may be needed in the form of various temperature and humidity controlled coolers, freezers, etc.

There may be a commercial kitchen associated with the facility so that value-added products can be produced either by the farmers or by the food hub staff.

A storefront might be added so that the public can access food right at the hub instead of having all the food shipped out to other businesses.

It can act as a community supported agriculture (CSA) location or it might just focus on supplying restaurants, schools and institutions such as hospitals and prisons.

Another idea would be to include space for education, training producers and consumers in efficient methods of local food production and delivery. Its shape will be defined by the needs of the surrounding community.

Cornell Cooperative Extension recently received a grant to gather some preliminary information hopefully leading to the establishment of several food hubs in the Adirondack region. Or maybe not. The point of the study is to see how many farmers are interested and willing to sell to a food hub, what products they have and what their production capacity is.

While many think a food hub would be a great idea, few appear ready to participate. Many of our local farmers are struggling to make ends meet with full retail dollars and are understandably reluctant to shift toward wholesale pricing structures or even something in between. For a food hub to work, producers and consumers all need to be on board.

And food safety, from suppliers through distribution has to be valued.

Fine dive

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Ashley Chaifetz, a PhD student studying public policy at UNC-Chapel Hill writes:

As a food policy doctoral student, I pay special attention to articles on food waste and its prevention—which includes dumpster diving. This activity is at the intersection of policies on food insecurity, waste, safety, and liability—and comes with a lot of uncertainties.   This week, Tove Danovich wrote about dumpster diving for Civil Eats:

Dumpster divers of the world, unite. Last week, food waste activist Rob Greenfield offered to pay the fines and bring some media attention to anyone who gets arrested or ticketed for taking and eating tossed food.Image 2

Greenfield has been drawing attention to food waste by traveling the country, engaging local communities, and photographing the enormous quantities of wasted food he finds. Now he hopes more Americans will begin looking at the problem directly by trying it themselves by taking people’s fear of arrest and fines out of the equation.

“From what I can tell the main reason that people don’t dumpster dive is the fear of getting arrested or ticketed,” wrote Greenfield recently on his website.

Rob Greenfield makes an effort to remind people about the problem of food waste. At a loss rate of approximately 40%, Americans are tossing almost as much food as they consume. But, Greenfield’s suggestion that people do not dumpster dive due to fines seems ludicrous; it is probably due to the products.

The issue with dumpster diving that is often forgotten is food safety. Neither Greenfield nor any other dumpster diver can tell via taste or smell if the food was tossed due to pathogen contamination. Even when if food is thrown away due to cosmetic reasons, the dumpsters themselves are not clean and sanitized like a food contact surface. If a product contaminated with a pathogen was discarded into the dumpster, the products pulled by the dumpster divers may be contaminated as well.

Individuals concerned with food safety can take other actions to lessen food waste: consuming all of the food purchased, choosing the “reduced for quick sale” items, shopping in salvage grocery stores, or even encouraging large grocery chains to donate those items to food pantries and food banks (many which already do).

And so it goes: Marj’s closes following hepatitis A exposure event

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When a restaurant’s food safety practices are called into question isn’t usually good business. The restaurant industry isn’t the most stable at the best of times.

Anecdotally, vocal and passionate community members support a local diner or meeting place, even after illnesses; but sales still often plummet.

In 2010, salmonellosis hit 60+ patrons of a Durham, NC BBQ joint, Bullocks. Sam Poley, marketing director for the Durham Convention & Visitors Bureau said, “This is a long-standing restaurant … 58 years in business … never had anything less than an ‘A’ health rating.” Sales dropped 80% and the usually busy restaurant was close to empty.logo

Three days after being linked to a hepatitis A exposure (where an ill cook was diagnosed with the virus, Marj’s, the Alma, Ontario institution closed it’s doors. According to CTV, owner Keith McLean released the following statement:

There are several factors for Marj’s Village Kitchen Inc. closing, economic times, the remote location for winter traffic, the restaurant has been struggling financially and now the reputation has been tainted.

There has been a serious cash flow problem resulting from this last incident. It is important that staff and patrons seek medical attention, even though the chances are next to nil of contracting this condition from Marj’s.

There has been an outpouring of concern about Marj’s. Management would thank those individuals for their past patronage plus their well wishes. Thank you sincerely.

 

 

Bakery owner: It’s easy to follow the rules; good food safety is about staff who care

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Employing good food safety at retail is a combination of folks identifying risks and putting in mitigation steps to address them. The rub is that you need to cultivate a good staff who values the stuff that keeps patrons from getting sick. The science and guidance is relatively easy compared to the people stuff.

Mad Eliza’s Cakes and Confections, a pastry and bakery shop in Topeka, KS sorta has the people stuff figured out, according to cjonline.com.bakery-www

“It doesn’t matter what it is,” said co-owner Mark Murnahan, “I’m going to see it if it’s dirty.”

Murnahan said he has pretty high standards for his kitchen staff of four and constantly monitors everything to make sure they are in compliance. The KDA food guidelines, he said, are never farther than his laptop.

“I don’t want to serve anything I wouldn’t serve to my 98-year-old grandma or my 1-year-old son or anyone in between,” he said.

To accomplish that, Murnahan said, “training is critical” — and so is having a staff that cares about what it is serving.

“You have to know someone will take direction and have pride in what they serve,” he said. “Anyone who really wants to learn, the first thing they need to learn is food safety.”

“Anybody can have a good inspection,” Murnahan said. “It’s not hard to follow the rules. There are a lot, but once you know them, they’re really not hard to follow.”

Going public: The California Salmonella outbreak no one knew about

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Laurel Maloy of Food Online writes that state and local public health officials have a responsibility to inform the public. In this particular incident… it didn’t happen

brent's.deliDuring the summer of 2014, 21 people fell ill after eating at Brent’s Deli in Westlake Village, CA. However, no one, except the people who suffered, the public health officials, and the owners of the deli were ever made aware of the outbreak.

The outbreak first came to light when seven people living in Ventura and Los Angeles counties were identified as being infected with a somewhat uncommon genetic strain of Salmonella Montevideo. Patient interviews turned the attention to Brent’s Deli. Eventually 19 patients were diagnosed with S. Montevidea (JIXX01.0645), and another two diagnosed with JIXX01.1565, a clonal offshoot of the outbreak strain. The strains were positively identified through the use of pulsed field gel electrophoresis (PFGE) performed by the California Department of Public Health’s (CDPH) Microbial Disease Laboratory (MDL). Two of the infected patients were employees of the deli. And still, the outbreak was kept under wraps, a remarkable feat in and of itself when you consider the speed with which information normally travels today.  If just one ill person had posted about it via social media, this outbreak would not have gone unnoticed.

According to Bill Marler’s blog, he was notified by Trevor Quirk, a California attorney, who was retained by one of the outbreak victims.

The onset of illnesses occurred on April 30, 2014, with illnesses from this same outbreak being identified as late as August 16, 2014. The largest numbers of patients were reported in June and August, with eight patients requiring hospitalization. What stands out is that though the onset of illness can be tracked back to April, with a significant cluster in June, it wasn’t until mid-July that the MDL raised the level of awareness. Apparently the Centers for Disease Control and Prevention (CDC) was never brought into the loop.

brent's.deli.reubenOn July 9 the Environmental Health (EH) staff of Ventura County performed an on-site inspection at the Deli. During the inspection, numerous violations — including sanitation, storage, and cooling problems — were discovered. The manager was directed by EH to immediately take action to correct the violations. A follow-up inspection occurred on July 22, with major violations again observed and annotated.

Though it may seem surprising that this outbreak was not elevated to warrant at least a local news report, no laws were broken. Unless an outbreak involves a large number of people or affects people in many states, Federal agencies, such as the CDC,  may or may not be called in. The question then, is: “How many people constitutes a large number?” It is also common for a state health department to work with the state department of agriculture when more than one city or county is involved.  That did not happen, though two counties, Los Angeles and Ventura, saw patients.

The CDC defines a foodborne-disease outbreak (FBDO) as “an incident in which two or more persons experience a similar illness resulting from the ingestion of a common food.” If you look at the timeline, one case was identified on April 27, another on May 18, one on June 1 and then two on June 8. The largest number of confirmed cases, three, happened on June 29, but no action was taken until July 18.

Consider this — what if the unsanitary conditions at Brent’s Deli was discovered before the outbreak? These conditions evidently existed, but went undiscovered, for an extended period of time. An unscheduled short visit from EH would have led to a more thorough inspection.  What if,  after the first two cases, someone had thought to warn the public or to immediately question the patients on where they had eaten? What if the first inspection at Brent’s Deli had been conducted in early June, rather than in late July?  There are any number of solutions that could have been implemented to prevent illnesses.

Anyone in the food-processing industry — from farms providing processors with raw products to the delivery person that supplies corned beef to the local deli — has a moral responsibility to report. The industry can, to a great extent, police itself. It simply takes a commitment to be aware and to get involved to prevent the blatant conditions that cause foodborne illnesses, hospitalizations, and death.