Epi works: Over 300 sickened from crypto on pre-cut salad greens in UK, 2012

In May 2012, people in England and Scotland started getting sick with Cryptosporidium. In June, 2012, the UK Health Protection Agency first announced 267 people were sick with Cryptosporidium across four areas of the UK, double the normal rate.

lettuce.harvestTen months later, HPA said the crypto that sickened about 300 people was most likely linked to eating pre-cut bagged salad products which were likely to have been labeled as ‘ready-to-eat.’

The outbreak was short lived and the numbers of cases returned to expected seasonal levels within a month of the first cases being reported. Most of those affected had a mild to moderate form of illness and there were no deaths associated with the outbreak.

During the investigation, an initial link was found between illness and pre-cut spinach. When specific retailers were included in the analysis, the strongest association with infection was found to be with consumption of ready to eat pre-cut mixed salad leaves from a major supermarket chain.

In this analysis, exposure to pre-cut spinach only reached conventional levels of significance for one retailer – a second major supermarket chain. A link to spinach from a number of other retailers was also suggested but these were not statistically significant. Together these findings suggest that one or more types of salad vegetables could have been contaminated.

Dr Stephen Morton, regional director of the HPA’s Yorkshire and the Humber region and head of the multi-agency Outbreak Control Team, said, “Our findings suggest that eating mixed leaf bagged salad was the most likely cause of illness. It is however often difficult to identify the source of short lived outbreaks of this type as by the time that the outbreak can be investigated, the affected food and much of the microbiological evidence may no longer be available

Dr Alison Gleadle, director of food safety at the FSA, took the opportunity to further confuse consumers, stating, “We’d like to remind everyone of our usual advice to wash all fruits and vegetables, including salad, before you eat them, unless they are labeled ready-to-eat.”

lettuce.skull.e.coli.O145But wasn’t this outbreak linked to ready-to-eat salads? How is that advice of any use? Could have offered some details, like, additional washing of ready-to-eat products is largely ineffective. FSA is refocusing its efforts on farm management to limit such contamination, before it happens.

A spokesthingy from retailer Morrisons said, rather defensively, “Morrisons is not the source of this outbreak. We have received no complaints of illness and no Morrisons products have tested positive for Cryptosporidia.

“The HPA’s claim is based solely on statistics, not testing. The very same statistics also implicated products from other retailers that the HPA recognize as ‘implausible’.”

Why doesn’t Morrison’s say what they do to enhance the safety of products they sell rather than trash epidemiology?

In the scientific paper on the outbreak, McKerr et. al reported a widespread foodborne outbreak of Cryptosporidium parvum in England and Scotland in May 2012. Cases were more common in female adults, and had no history of foreign travel. Over 300 excess cases were identified during the period of the outbreak. Speciation and microbiological typing revealed the outbreak strain to be C. parvum gp60 subtype IIaA15G2R1.

METHODS: Hypothesis generation questionnaires were administered and an unmatched case control study was undertaken to test the hypotheses raised. Cases and controls were interviewed by telephone. Controls were selected using sequential digit dialling. Information was gathered on demographics, foods consumed and retailers where foods were purchased.

RESULTS: Seventy-four laboratory confirmed cases and 74 controls were included in analyses. Infection was found to be strongly associated with the consumption of pre-cut mixed salad leaves sold by a single retailer. This is the largest documented outbreak of cryptosporidiosis attributed to a food vehicle.

An outbreak of cryptosporidium parvum across England & Scotland associated with consumption of fresh pre-cut salad leaves, May 2012

PubMed

McKerr C1, Adak GK2, Nichols G3, Gorton R4, Chalmers RM5, Kafatos

PLoS One, 2015, doi: 10.1371/journal.pone.0125955. eCollection 2015.

http://www.ncbi.nlm.nih.gov/m/pubmed/26017538/

Salmonella positive triggers habanero pepper recall

Montero Farms of McAllen, Texas is recalling Orange Habanero Peppers, because they have the potential to be contaminated with Salmonella.

salm.pepper.recallOrange Habanero Peppers were shipped to Indianapolis, Indiana and to McAllen, Texas from April 28 2016 to present.

The product comes in 8 pound cardboard boxes marked with lot #41142-41143 on the top. In total 154 boxes are being recalled.

No illnesses have been reported to date in connection with this problem.

The potential for contamination was noted after routine testing by the FDA.

Production of the product has been suspended while FDA and the company continue their investigation as to the source of the problem.

Are ready-to-eat salads ready to eat?

We investigated a nationwide outbreak of Salmonella Coeln in Norway, including 26 cases identified between 20 October 2013 and 4 January 2014. We performed a matched case-control study, environmental investigation and detailed traceback of food purchases to identify the source of the outbreak.

lettuce.skull.noroIn the case-control study, cases were found to be more likely than controls to have consumed a ready-to-eat salad mix (matched odds ratio 20, 95% confidence interval 2·7–∞). By traceback of purchases one brand of ready-to-eat salad was indicated, but all environmental samples were negative for Salmonella.

This outbreak underlines that pre-washed and bagged salads carry a risk of infection despite thorough cleaning procedures by the importer. To further reduce the risk of infection by consumption of ready-to-eat salads product quality should be ensured by importers.

Outbreaks linked to salads reinforce the importance of implementation of appropriate food safety management systems, including good practices in lettuce production.

Are ready-to-eat salads ready to eat? An outbreak of Salmonella Coeln linked to imported, mixed, pre-washed and bagged salad, Norway, November 2013

F. Vestrheima1a2 c1, H. Langea1a3, K. Nygårda1, K. Borgena1, A. L. Westera1, M. L. Kvarmea4 and L. Volda1

Epidemiology and Infection, Volume 144, Issue 8, June 2016, pages 1756-1760, DOI: http://dx.doi.org/10.1017/S0950268815002769

http://journals.cambridge.org/action/displayAbstract?fromPage=online&aid=10299069&utm_source=Issue_Alert&utm_medium=RSS&utm_campaign=HYG

Version II: Don’t eat poop, and if you do, cook it

The link in the previous story was wrong, but now corrected thanks to an eagle-eyed readerer.

french.dont.eat.poopHere’s another version about the latest don’t eat poop paper.

Consumers don’t buy leafy greens and other healthy supermarket produce anticipating the food might make their families sick. Or at least, they didn’t used to.

But high profile recalls of fruits and veggies seem to be a new normal in the American food landscape. The recalls follow outbreaks of foodborne illnesses caused by microbes like E. coli. These outbreaks can send unsuspecting veggiephiles rushing to the nearest toilet or, worse yet, the hospital. Some outbreaks can even result in deaths.

The average American is still unlikely to wind up at the emergency room after eating tainted produce. Still, outbreaks have major consequences for supermarkets and growers. After outbreaks, they must regain public trust or face possible financial ruin.

Of concern is how nearby farming practices can taint produce with bacteria. This can happen when farmers apply animal manure to fields near fresh produce. Tiny particles, including bacteria, may go airborne and drift to nearby fields. But scientists weren’t sure just how likely microbes can travel from manure application sites to downwind produce.

That is, until now. New field research out of Clarkson University in upstate New York is providing an answer. Shane Rogers, an associate professor of civil and environmental engineering, led a research team that looked into the issue. They measured how far common bacteria, including Salmonella and E. coli, are likely to travel downwind from manure application sites. They hoped to better understand how fresh produce might be contaminated by nearby animal agriculture practices.

“Our goal was to provide a logical framework to study this pathway,” Rogers said. This helped them make science-based recommendations for setback distances that protect human health.

The team used field data to understand how these bacteria travel from manure application sites to produce. The research lasted three years. They took samples at several distances from manure application sites and measured the presence of illness-causing bacteria.

The researchers used computer models to expand their understanding. “It is not possible to obtain measurements for every possible set of circumstances that may exist,” Rogers said. “The models allow us to predict produce contamination over a larger range of probable conditions than our raw measurements would provide.” These include the type of manure, the terrain of the farm, and weather conditions at the time the manure is applied.

The team also evaluated the risk of illness. This gave the team a better understanding of how likely someone is to get sick from produce when a certain amount of bacteria is present.

Combining all that data, the team found that produce fields should be set back from areas of manure application by at least 160 meters. That distance should help lower the risk of foodborne illness to acceptable levels (1 in 10,000).

Rogers emphasized that the advice is for a minimum setback. “(160 meters is) the minimum distance that produce growers should maintain between manure application activities and produce growing areas,” Rogers said. Additional distance and delay between manure application and harvest would provide further protection.

The study appears in Journal of Environmental Quality. This project was supported by National Research Initiative Competitive Grant and the Agricultural Food and Research Initiative (AFRI) from the National Institute of Food and Agriculture (NIFA) Air Quality Program.

American Society of Agronomy

Michael A. Jahne, Shane W. Rogers, Thomas M. Holsen, Stefan J. Grimberg, Ivan P. Ramler, Seungo Kim

Journal of Environment Quality, 45 (2): Page 666 DOI:10.2134/jeq2015.04.0187

https://www.sciencedaily.com/releases/2016/04/160413140124.htm

Don’t eat poop, and if you do, cook it: Manure application research aims to improve food safety

New field research out of Clarkson University in upstate New York is attempting to answer how likely microbes can travel from manure application sites to downwind produce.

lettuce.skull.noroShane Rogers, an associate professor of civil and environmental engineering, led a research team that looked into the issue. They measured how far common bacteria, including Salmonella and E. coli, are likely to travel downwind from manure application sites. They hoped to better understand how fresh produce might be contaminated by nearby animal agriculture practices.

“Our goal was to provide a logical framework to study this pathway,” Rogers said. This helped them make science-based recommendations for setback distances that protect human health.

The team used field data to understand how these bacteria travel from manure application sites to produce. The research lasted three years. They took samples at several distances from manure application sites and measured the presence of illness-causing bacteria.

The researchers used computer models to expand their understanding. “It is not possible to obtain measurements for every possible set of circumstances that may exist,” Rogers said. “The models allow us to predict produce contamination over a larger range of probable conditions than our raw measurements would provide.” These include the type of manure, the terrain of the farm, and weather conditions at the time the manure is applied.

The team also evaluated the risk of illness. This gave the team a better understanding of how likely someone is to get sick from produce when a certain amount of bacteria is present.

Combining all that data, the team found that produce fields should be set back from areas of manure application by at least 160 meters. That distance should help lower the risk of foodborne illness to acceptable levels (1 in 10,000).

Rogers emphasized that the advice is for a minimum setback. “(160 meteårs is) the minimum distance that produce growers should maintain between manure application activities and produce growing areas,” Rogers said. Additional distance and delay between manure application and harvest would provide further protection.

 

McKenzie brothers can explain: ‘We recently found a whole mouse in an energy drink’

This week, Cynthia Mangione, a food laboratory specialist at the New York State Department of Agriculture and Markets, and Stephanie Brock, a radiation health supervisor at the Kentucky Department for Public Health, took to Reddit to answer questions about their jobs. They spend their days “testing products imported into the US for dangerous pathogens, as well as illegal dyes, metals, antibiotics and more.” Here are the three most surprising reveals:

mouse.beer2) The one food safety testers avoid eating: sprouts

I have given up sprouts because of ongoing concerns with their safety. We also make sure to wash ready-to-eat veggies (despite the “triple wash” designation).

According to the Food and Drug Administration’s food safety website, sprouts — such as alfalfa, clover, radish, and mung bean sprouts — are a higher-risk food. This is because they are eaten raw and, unlike other fresh produce, need to grow in warm and humid environments — the ideal breeding grounds for dangerous bacteria such as salmonella, listeria, and E. coli. Washing them doesn’t always kill that potentially harmful bacteria.

Since 1996, there have been more than 30 outbreaks in the US associated with sprouts. In a recent analysis of food outbreaks in the US, sprouts were among the leading culprits.

3) The craziest thing they found in a food they tested…

We recently found a whole mouse in an energy drink!

Can’t really explain this one, but it’s pretty disturbing.

Where did the Listeria come from? US outbreak of listeriosis linked to Dole salads appears over

A couple of days after the Canadians wrapped up their investigation, the U.S. Centers for Disease Control and Prevention has issued its own final report on the Listeria outbreak linked to packaged salads produced at a Dole Processing Facility in Springfield, Ohio.

160122-dole-salad-mn-1530_8b681a6748a4253c3ec1c087b4cd8b0d.nbcnews-fp-1200-800CDC, several states, and the U.S. Food and Drug Administration (FDA) investigated a multistate outbreak of Listeria monocytogenes infections (listeriosis).

A total of 19 people infected with the outbreak strain of Listeria were reported from nine states.

All 19 people were hospitalized, and one person from Michigan died as a result of listeriosis. One illness was reported in a pregnant woman.

Whole genome sequencing (WGS) performed on Listeria isolates from all 19 ill people showed that the isolates were closely related genetically.

According to the Public Health Agency of Canada, ill people in Canada were infected with the same outbreak strain of Listeria.

WGS performed on clinical isolates from ill people in Canada showed that the isolates were closely related genetically to Listeria isolates from ill people in the United States.

Epidemiologic and laboratory evidence indicated that packaged salads produced at the Dole processing facility in Springfield, Ohio and sold under various brand names were the likely source of this outbreak.

On January 27, 2016, Dole voluntarily recalled all salad mixes produced in the Springfield, Ohio processing facility. Any recalled salad mixes still on the market or in consumers’ homes would be past their expiration dates.

29 sick, 3 dead: Canadians wrap up Dole listeria investigation

Doug Carder of The Packer reports the Public Health Agency of Canada has wrapped up its investigation into a listeria outbreak linked to Dole Fresh Vegetables Inc.’s processing plant in Springfield, Ohio, that infected more than a dozen Canadians.

listeria4“Given that the source of the outbreak was identified and contaminated products have been recalled from the market, the outbreak investigation coordinating committee has been deactivated and the investigation is coming to a close,” according to a report posted on the Canadian health agency’s website regarding the investigation which began in late January.

The agency investigated 14 cases of Listeria monocytogenes in five Canadian provinces: Ontario (9), Quebec (2), New Brunswick (1), Prince Edward Island (1), and Newfoundland and Labrador (1), according to the report. Individuals became ill between May 2015 and February, the agency reported.

“All cases have been hospitalized, and three people have died, however it has not been determined if listeria contributed to the cause of these deaths,” according to Public Health Agency of Canada’s final report.

Dole reported Jan. 21 to U.S. health officials with the Food and Drug Administration and the Centers for Disease Control and Prevention that it had suspended operations at the Ohio plant once it learned of the possible connection to the listeria outbreak. On Jan. 27, the company voluntarily recalled all Dole and private-label packaged salads produced there.

FDA confirmed Jan. 28 the presence of Listeria monocytogenes in a packaged salad produced at the Springfield plant.

As of Feb. 25, the CDC had reported the outbreak had infected 18 people in nine states. All cases required hospitalization, according to CDC.

Laboratory results from the Canadian Food Inspection Agency confirmed a link between recalled packaged salad products and the listeria outbreak in Canada, according to the report. Lab results “confirmed that the Canadian and U.S. listeria outbreaks are highly genetically related,” according to the Canadian health agency’s report.

While Canadian health officials have concluded their investigation, the U.S. investigation into the outbreak remains active, according to FDA.

It’s not the curves, it’s the oxygen groups: Viral attachment to produce

In an effort to understand and eventually reduce the incidence of foodborne illnesses, University of Illinois researchers studied the ability of pathogenic viruses to adhere to fresh produce surfaces.

lettuce“We chose 24 of the most common salad vegetables in the U.S. and assayed them to see if there was any relationship between the morphology and chemistry of the leaf or fruit surface and the adherence of viral particles, before and after a washing treatment,” says U of I geneticist Jack Juvik.

The researchers inoculated leafy salad greens and tomatoes with a swine virus that mimics human rotavirus, a common pathogen responsible for diarrhea, vomiting, fever, and abdominal pain. After exposing the vegetable surfaces to the virus, the researchers rinsed the vegetables twice with a standard saline solution.

“We correlated virus adherence to roughness of the surface at different scales. We also looked at the chemistry of the proteins and waxes associated with the leaf cuticle – a waxy layer that protects the plant against diseases and reduces water loss,” Juvik explains. “Before this, no one had tested the relationship between chemistry and surface texture on the adherence of virus particles.”

The researchers found a thousand-fold difference in the number of viral particles adhering to different types of leafy greens and tomatoes. Vegetables with three-dimensional crystalline wax structures on the leaf cuticle harbored significantly fewer virus particles after rinsing. This was counterintuitive, as it was expected that small virus particles could “hide” in the rough structures of these cuticles.

lettuce.nov10“I was surprised, too,” Juvik says. “But normally, viruses adhere to oxygen groups, like OH, which are associated with proteins and carbohydrates on the surface. When the wax completely covers the surface, it becomes totally hydrophobic, which renders the whole leaf surface harder for viruses to attach to. Furthermore, rinsing those leaves with water gives the viruses the OH groups they’re looking for, so they’re easier to wash away.”

Produce is exposed to viruses and other pathogens in a number of ways, including contaminated irrigation water, animal wastes, and handling by sick workers. But because salad vegetables are consumed fresh, pathogens cannot be killed by cooking or most other sterilization methods.

“Viruses are literally everywhere, causing many opportunities for infection. But the information from this study can be used down the road to select or breed for varieties that might have the capacity to reduce adherence of these particles,” Juvik explains.

The researchers have already repeated the study using the bacterium E. coli, but they plan to look at even more vegetable varieties and pathogens in future studies.

The article, “Influence of epicuticular physiochemical properties on porcine rotavirus adsorption to 24 leafy green vegetables and tomatoes” was published in PLOS One. The study was led by Lu Lu, whose co-authors included Juvik, Kang-Mo Ku, Sindy Paola Palma-Salgado, Andrew Page Storm, Hao Feng, and Thanh Nguyen, all from the University of Illinois. The project received funding from the USDA’s National Institute of Food and Agriculture.