Rewashing triple-washed greens at home can only increase risk of foodborne illness

Keeping with the pathogen-in-leafy-greens theme of the night, I buy the triple washed and the never washed types of lettuce. My decision is usually based on how much we’ll consume in the next few days. I rinse the not washed. For the triple-washed type I open the bag and consume.

Stephen Kearse of Slate asks, What does “triple-washed” actually mean? And why do salad-green producers brag about washing their lettuce not twice, not four times, but three times in particular?USC1009846_026

I initially took my questions to salad-green producers themselves. Of the few companies that responded, most were tight-lipped. “We don’t discuss our business practices,” I was told by the PR director of Trader Joe’s, as if I were a rival firm rather than a customer. “Unfortunately we won’t be able to participate with input for your article,” I was told by the communications director of Dole, as if talking about food were beyond the scope of Dole’s business interests.

Earthbound Farms and Ready Pac were less reserved, offering to take some of my questions and answering them through email, but these exchanges were chillingly mediated, routed through an opaque infrastructure of internal approvals. The answers I received seemed like they had been triple-washed themselves, scrubbed of any negative (or meaningful) content. “From planting to harvest, each stage is inspected and audited to ensure it meets our strict food safety standards,” Earthbound told me. “Ready Pac Foods has long been at the forefront of innovation in safety and quality,” I was told by Ready Pac. I knew when I set out to understand “triple-washed” that I was scratching at the surface of ad copy, but I didn’t expect to find more copy underneath.

Ben Chapman, a food safety specialist and researcher at North Carolina State University, explained that triple washing is at least partially an aesthetic preparation. Triple washing is “not just a food safety step,” he said. “It’s a quality step as well.” The lettuce and other greens that go into our salads are grown in sprawling fields full of soil, rocks, sand, and dust. Because greens are eaten raw, any of these elements could potentially make it onto a plate. The triple-wash process greatly reduces the chance of this happening, removing “dirt, debris, anything you might find associated with the environment when you’re harvesting lettuce,” Chapman informs me. So one of the reasons salad producers love to tout the triple-washed process is that it really does help ensure the purity of greens.

But that doesn’t mean greens that have been cleaned of debris are necessarily free of dangerous microbes. Where the triple-washed label becomes dicey is at the level beyond visual perception. Triple-washed greens aren’t necessarily washed with water—in fact, they’re generally washed with sanitizers and other compounds that are intended to reduce pathogens, according to the food safety literature. But Chapman says these substances only tend to eliminate 90 to 99 percent of the microbes. “Only” may seem like a strange word choice for such a drastic decrease, but in microbiology, effectiveness is measured in log reductions, which are tenfold, meaning that each log reduction decreases bacteria to 10 percent of their initial number. A 90- to 99-percent decrease is only a one- to two-log reduction. Because pathogens can exist in superabundance, on a microbial level, a one- to two-log reduction means that there are still enough remaining pathogens to cause and spread illness.

And even a fourth or fifth wash would not reliably drive that number down, because some pathogens ensconce themselves inside the grooves of leaves like hermit crabs in shells, finding microscopic coves that are unreachable by liquids. Citing a 2007 paper published in Food Protection Trends, Chapman informs me that washing at home actually increases the risk of contamination because surfaces at home are likely crawling with germs. “I can’t do any better with the tools I have at my home than what the processor did. There’s no net risk reduction potential for me to wash. I am literally not doing anything by washing it at home,” he` dryly reports. The only way to amp up that log reduction would be to apply heat, which will produce a supersafe five- to seven-log reduction but also ruin your salad.

So triple washing is a tortured compromise with an inconvenient reality: Salad greens aren’t particularly conducive to consumer safety. From its structural ability to harbor pathogens, to its inability to withstand heat, to its wide surface area, to the fact that it is processed in large volumes (increasing the risk of cross-contamination), commercial lettuce is as outbreak-ready as a 14th-century marmot.

What prevents frequent outbreaks (or rather what can prevent outbreaks) is the system of practices that begin long before the lettuce is washed thrice. There’s a sprawling matrix of voluntary audits, mandated inspections, legislation, certifications, research, services, and training available to ensure that salad is safe before it reaches a consumer or a wash basin. The practices that this matrix targets vary depending on the size of the farm and even the species of greens, but the general questions are straightforward. Are crops segregated from animal pins? Are compromised crops being discarded? Are workers wearing gloves? Are storage facilities regularly cleaned? Are wash waters coming from a safe source? These questions may seem basic, but asking them and acting on them can be the difference between life and death.

Although this matrix is not fail-safe, Chapman insists, it does have the potential to prevent outbreaks, but only when buyers (retailers and consumers alike) look at the practices underlying passed inspections and growers actually apply those practices on days other than inspection day.

Food Safety Talk 100: No buns in the bathroom

Food Safety Talk, a bi-weekly podcast for food safety nerds, by food safety nerds. The podcast is hosted by Ben Chapman and barfblog contributor Don Schaffner, Extension Specialist in Food Science and Professor at Rutgers University.  Every two weeks or so, Ben and Don get together virtually and talk for about an hour.1459283728049

They talk about what’s on their minds or in the news regarding food safety, and popular culture. They strive to be relevant, funny and informative — sometimes they succeed. You can download the audio recordings right from the website, or subscribe using iTunes.1461946810971

Episode 100 can be found here and on iTunes.

Here is a bulleted list of link to the topics mentioned on the show:

4 dead, 33 ill from Listeria in lettuce: Of course Dole knew

Beginning August 2, 1998, over 80 Americans fell ill, 15 were killed, and at least six women miscarried due to listerosis. On Dec. 19, 1998, the outbreak strain was found in an open package of hot dogs partially consumed by a victim. The manufacturer of the hot dogs, Sara Lee subsidiary Bil Mar Foods, Inc., quickly issued a recall of what would become 35 million pounds of hot dogs and other packaged meats produced at the company’s only plant in Michigan. By Christmas, testing of unopened packages of hot dogs from Bil Mar detected the same genetically unique L. monocytegenes bacteria, and production at the plant was halted.

four.monkeysA decade later, the deaths of two Toronto nursing home residents in the summer of 2008 were attributed to listeriosis infections. These illnesses eventually prompted an August 17, 2008 advisory to consumers by the Canadian Food Inspection Agency (CFIA) and Maple Leaf Foods, Inc. to avoid serving or consuming certain brands of deli meat as the products could be contaminated with L. monocytogenes. When genetic testing determined a match between contaminated meat products and listeriosis patients, all products manufactured at a Toronto Maple Leaf Foods plant were recalled and the facility closed. An investigation by the company determined that organic material trapped deep inside the plant’s meat slicing equipment harbored L. monocytogenes, despite routine sanitization that met specifications of the equipment manufacturer. In total, 57 cases of listeriosis as well as 22 deaths were definitively connected to the consumption of the plant’s contaminated deli meats.

As far back as 2013, Blue Bell ice cream was finding Listeria in places like floors, catwalks and cleaning tubs. Blue Bell had positive listeria findings from at least 11 swabs of plant surfaces between March 2013 and November 2014. Each time, it vigorously cleaned the area, and moved on without testing the equipment that touches the ice cream. At the same time, Blue Bell had problems with the layout of its plants, with condensation dripping all over the place. After federal officials linked an illness outbreak to Blue Bell in 2015, they tested the company’s food processing equipment and found LM. Three people died and 10 were sickened.

In all three Listeria outbreaks, the companies had data that showed an increase in Listeria-positive samples.

But rather than pay attention, they ignored the safety.

Those who study engineering failures –the BP oil well in the Gulf, the space shuttle Challenger, Bhopal – say the same thing: human behavior can mess things up.

listeria4In most cases, an attitude prevails that is, “things didn’t go bad yesterday, so the chances are, things won’t go bad today.”

And those in charge begin to ignore the safety systems.

Or hope the problem will just go away.

Kellogg’s was taking Salmonella-contaminated peanut paste based on paperwork in 2009? Pay attention, Nestle did.

In 2009, the operator of a yakiniku barbecue restaurant chain linked to four deaths and 70 illnesses from E. coli O111 in raw beef in Japan admitted it had not tested raw meat served at its outlets for bacteria, as required by the health ministry.

“We’d never had a positive result [from a bacteria test], not once. So we assumed our meat would always be bacteria-free.”

Chipotle Mexican Grill was aware of a norovirus outbreak among people who had eaten in one of its restaurants in Simi Valley, Calif., but did not tell public health officials there until after it had closed and cleaned the restaurant. More than 200 people were sickened.

So it’s no surprise that officials at Dole’s Springfield, Ohio plant, which bags lettuce and other supposedly healthy meals, knew about Listeria in its facility for 18 months before shutting down and issuing a recall.

Four people have died and 33 sickened in Canada and the U.S. from Listeria in the Dole products.

Kudos to Bill Marler and his Food Safety News, as well as Food Poisoning Bulletin, for filing the Freedom of Information request on U.S. Food and Drug Administration inspections at the Dole plant and putting together a preliminary picture of who knew what when.

Inspection reports (483) obtained by Food Safety News revealed the timeline of positive Listeria results and inaction. Dole Fresh Vegetables Inc. finally suspended production at its salad plant in Springfield, OH, on Jan. 21 this year after a random test by state officials showed a bagged salad contained Listeria monocytogenes.

Dole restarted production at the plant in Springfield, OH, on April 21. Company officials won’t say what was done to clean the plant or how they plan to prevent future contamination there.

powell_soli_AUG2Inspectors from FDA checked the production plant three times in January and twice in February after genetic fingerprinting showed the undeniable link between the sick people and salads from the facility. They collected swab samples, unfinished product samples, testing records and other documents and information.

According to the FDA’s inspection reports, in July 2014 Dole did swab tests of surfaces in the Springfield plant. The tests returned positive results for Listeria, but the facility kept producing salads, shipping them to dozens of states and at least five Canadian provinces.

At least five more times in 2014 and three times in late 2015 Dole’s internal tests showed Listeria contamination, but Dole kept the salad lines kept rolling until January this year.

The FDA inspection report states that Dole’s vice president for quality assurance and food safety, as well as the company’s quality assurance manager, were aware internal tests on Jan. 5 and 7 this year showed Listeria on equipment and other surfaces in the plant. But Dole continued to produce and ship salads.

The plant kept operating until Jan. 21. The following day Dole posted a recall notice with the FDA and the Canadian Food Inspection Agency (CFIA) for salads produced at the Springfield facility. Dole branded salads and house brands for Walmart, Kroger, Loblaws and Aldi were included in the recall.

Marler, a prominent food safety lawyer who represents one of the victims in a lawsuit against Dole told Stephanie Strom of the N.Y. Times, “If the government inspectors hadn’t showed up, who knows when or if they were going to tell anyone.”

“They’d been having positive tests for listeria for some time,” said William Goldfield, a spokesman for Dole. “We understand these recent news reports may raise questions among our consumers and customers. They should be assured, however, that we have worked in conjunction with the F.D.A. to address those observations and ensure that Dole products are safe.”

Lauren Sucher, a spokeswoman at the F.D.A., said that companies must notify the agency when they find a food has a “reasonable probability” of causing serious adverse health consequences.

But, Ms. Sucher said, not all strains of listeria cause disease. “When listeria is found in the manufacturing environment, rather than on the food itself, it is not uncommon for a company to immediately take corrective action rather than test further to see if the strain of listeria poses a threat,” she wrote in an email.

Food companies that find listeria during periodic testing are not required to run further tests to determine whether the pathogen is of a toxic variety.

In Dole’s case, it was swabbing various locations in its plant in Springfield, Ohio, not necessarily testing the finished products, according to the F.D.A. inspection. Rather, Canadian public health officials investigating an outbreak of listeriosis dating to summer 2015, tested bagged Dole salads and found four varieties that were contaminated.

Listeria in Italy: An on-going outbreak

In the first seven weeks of 2016, six cases of invasive listeriosis were recorded in Ancona province, Italy. Five strains of Listeria monocytogenes serotype 1/2a were isolated and typed by enterobacterial repetitive intergenic consensus (ERIC)-PCR and PFGE, indicating clonality. In addition, seven serotype 1/2a L. monocytogenes strains from cases of invasive listeriosis recorded in the same area in 2015 were also typed and showed relatedness. Here we provide details of the ongoing outbreak.

listeria4From 4 January to 15 February 2016, six L. monocytogenes strains (3 from blood, 3 from cerebrospinal fluid (CSF)) were isolated from six patients diagnosed with invasive listeriosis at the Clinical Microbiology Laboratory of Ancona Regional Hospital (eastern Italy) of Area Vasta 2 (AV2) which encompasses Ancona, Fabriano, Senigallia, and Jesi.

Patients had been admitted to four different departments: emergency room (ER) (n=2), oncology (n=2), infectious diseases (n=1), and intensive care unit (ICU) (n=1). Four of the six patients were women and the most common risk factors/underlying conditions were: age (n=5; >71 years), cancer (n=2), and diabetes (n=1). Clinical manifestations included septicaemia (n=3), meningitis (n=2) and meningoencephalitis (n=1).

In addition to the cases detected in 2016, eight L. monocytogenes strains (5 from blood and 3 from CSF) had been isolated in AV2 (from 7 cases) and nearby Ascoli Piceno (from 1 case) in 2015 (Figure 1); clinical samples came from six hospital departments: ER (n=1), general medicine (n=3), nephrology (n=1), vascular surgery (n=1), infectious diseases (n=1), and ICU (n=1). Five patients were men and the mean patient age was 73.6 years (range: 55–84; median: 75); a 77 year-old man died.

The 2015 and 2016 isolates were identified as L. monocytogenes by Gram staining and the Vitek MS system (bioMérieux Italia SpA, Firenze, Italy). Susceptibility to ampicillin, meropenem, erythromycin, and sulphamethoxazole-trimethoprim was tested by the E-Test (Liofilchem, Teramo, Italy) according to the European Committee on Antimicrobial Susceptibility Testing (EUCAST) guidelines [1]. All strains were susceptible to all the antibiotics tested.

The incidence of listeriosis has been rising since the early 2000s in several European countries, mainly in immunocompromised patients older than 65 years [7-9]. In particular, a statistically significant increase was reported in Austria, Denmark, Hungary, Italy, France, Spain, and Sweden from 2005 to 2009 [10]. In the past 30 years, outbreaks of listeriosis have been mostly linked to serotype 1/2a and 4b clones [8]. A shift to serotype 1/2a has been observed in Europe and North America in the last decade [8]. In Italy, surveillance of invasive listeriosis has found an increase in serotype 1/2a isolates over the same period, mainly in the central and northern regions (about 80% of cases) [10-14].

Listeriosis is an infection of great concern to public health due its clinical severity and high case fatality rate, despite its low incidence compared with other foodborne diseases such as salmonellosis or campylobacteriosis. The present data suggest an ongoing outbreak of listeriosis due to serotype 1/2a L. monocytogenes in AV2 that most probably started in 2015, since the strain was already present in the area in 2015. As in other European countries, most cases were associated with an underlying condition and involved elderly people [8,9].

Local authorities are working with the Italian national public health institute (the Istituto Superiore di Sanità, Rome) and the regional Istituto Zooprofilattico Umbria and Marche to identify the sources of food contamination. A recent press release [15] points out that there are findings which suggest contamination of a pork product as a possible vehicle of infection for at least one human case. At present, however, no clear link can be established between the contaminated pork product and the infections. Investigation into the source of infection in AV2 is still in progress.


Ongoing outbreak of invasive listeriosis due to serotype 1/2a Listeria monocytogenes, Ancona Province, Italy, January 2015 To February 2016

28 April 2016

Eurosurveillance, Volume 21, Issue 17

E Marini, G Magi, C Vincenzi, E Manso, B Facinelli

Damn that Listeria is tricky

Listeria monocytogenes is an important foodborne pathogen commonly isolated from food processing environments and food products.

listeria4This organism can multiply at refrigeration temperatures, form biofilms on different materials and under various conditions, resist a range of environmental stresses, and contaminate food products by cross-contamination. L. monocytogenes is recognized as the causative agent of listeriosis, a serious disease that affects mainly individuals from high-risk groups, such as pregnant women, newborns, the elderly, and immunocompromised individuals.

Listeriosis can be considered a disease that has emerged along with changing eating habits and large-scale industrial food processing. This disease causes losses of billions of dollars every year with recalls of contaminated foods and patient medical treatment expenses. In addition to the immune status of the host and the infecting dose, the virulence potential of each strain is crucial for the development of disease symptoms. While many isolates are naturally virulent, other isolates are avirulent and unable to cause disease; this may vary according to the presence of molecular determinants associated with virulence.

In the last decade, the characterization of genetic profiles through the use of molecular methods has helped track and demonstrate the genetic diversity among L. monocytogenes isolates obtained from various sources. The purposes of this review were to summarize the main methods used for isolation, identification, and typing of L. monocytogenes and also describe its most relevant virulence characteristics.

The continuous challenge of characterizing the foodborne pathogen Listeria monocytogenes

Foodborne Pathogens and Disease. April 2016, ahead of print. doi:10.1089/fpd.2015.2115.

Camargo Anderson Carlos, Woodward Joshua John, and Nero Luís Augusto

Canadian study finds soy can be used as an antibacterial agent

A new study from the University of Guelph has found soy can limit the growth of some bacteria, such as listeria and pseudomonas, and it does it better than chemical-based agents.

Soybeans-legumes“Current synthetic-based, chemical-based anti-microbial agents kill bacteria indiscriminately, whether they are pathogenic or beneficial,” researcher Suresh Neethirajan said.

The body – and in particular, the intestines – need good bacteria to properly process the food we eat.

The compounds in soybeans, however, do not kill off all bacteria, just the bad ones, Neethirajan said.

Soybean derivatives are already used in a variety of products including canned foods, cooking oils, meat alternatives, cheeses, ice cream and baked goods.

Neethirajan, an engineering professor and director of the BioNano Laboratory at the university, said those with soy allergies need not worry about soy being used to prevent bacteria growth.

He said their method isolates the active component of the soybean from the protein that causes allergic reactions. The soy isoflavones that are chemically similar to estrogen are also weeded out.

What is left is a compound that naturally stops the bad bacteria.

Neethirajan’s study will appear in the July edition of the journal Biochemistry and Biophysics Reports.

Food Safety Talk 99: Are you familiar with the Haugh Unit?

Food Safety Talk, a bi-weekly podcast for food safety nerds, by food safety nerds. The podcast is hosted by Ben Chapman and barfblog contributor Don Schaffner, Extension Specialist in Food Science and Professor at Rutgers University.  Every two weeks or so, Ben and Don get together virtually and talk for about an hour.

They talk about what’s on their minds or in the news regarding food safety, and popular culture. They strive to be relevant, funny and informative — sometimes they succeed. mm_Haugh_Tester-albumen

Episode 99 can be found here and on iTunes.

Don and Ben talk pickles, puppies, Lord Stanley and his cup, the Internet, eggs, coffee, deli slicers and cuisine from around the world. After Dark turns into taxes safety talk.

Below are some links to some of the things that they talked about:

New Zealand recalls spinach for Listeria positive

Southern Fresh Foods Ltd is recalling Delmark Baby Spinach 150gm, 500gm and 3kg packs after discovering that the product has tested positive for Listeria. identification

Product type: Ready to eat fresh salad

Name of product (size): Southern Fresh Foods brand Delmark Baby Spinach (150gm), Southern Fresh Foods brand Delmark Baby Spinach (500gm), Southern Fresh Foods brand Delmark Baby Spinach (3kg)

Batch numbers: 09703010

Date marking: Best Before dated 16th April 2016

Package size and description: Sold in 150gm and 500gm plastic packs and 3kg cartons.

Distribution: The product is sold in bulk to foodservice and some retail customers nationwide.

Customers are asked to check the batch number and date marking. Affected products should not be consumed. There have been no reports of illness, however if you have consumed any of these products and have any concerns about your health please seek medical advice.

Food Safety Talk 98: Klouty with a chance of meatballs

Food Safety Talk, a bi-weekly podcast for food safety nerds, by food safety nerds. The podcast is hosted by Ben Chapman and barfblog contributor Don Schaffner, Extension Specialist in Food Science and Professor at Rutgers University.  Every two weeks or so, Ben and Don get together virtually and talk for about an hour.1460412459633

They talk about what’s on their minds or in the news regarding food safety, and popular culture. They strive to be relevant, funny and informative — sometimes they succeed. You can download the audio recordings right from the website, or subscribe using iTunes.

Episode 98 can be found here and on iTunes.

This week Don and Ben open with the usual popular culture talk and then move into a discussion of norovirus-laden couches, Chipotle (again), and the safety of petting zoos. From there the discussion moves to lady balls, duck sliders, balls to the wall, and Blue Bell Ice Cream. The After Dark features more cowbell.

Below are some links to some of the things that they talked about:

Fresh From Texas recalls apple product because of Listeria

Fresh from Texas of San Antonio, Texas is voluntarily recalling multiple products containing sliced red apples which are identified below because they have the potential to be contaminated with Listeria monocytogenes,

No illnesses have been reported to date.

The product was sold by H-E-B stores in Texas.

The recall was the result of internal company testing which indicated the presence of Listeria Monocytogenes in two random samples of the same product. The company has ceased the production and distribution of the product as FDA and the company continue their investigation as to what caused the problem.