I do not buy stuff from the deli-counter. I buy stuff that is pre-packaged and may contain antimicrobials, depending on what country you are in.
It’s all about the slicers, whether it’s the little ones at the deli counter or the huge industrial ones in food facilities – I’m looking at you Maple Leaf, source of 23 dead in 2008 in Canada – and how hard they are to properly clean.
Should deli meats be served in hospitals or aged care facilities where the immunocompromised abound?
This outbreak is a reminder that people at higher risk for severe Listeria infection should handle deli-sliced meats and cheeses carefully to prevent illness. Pregnant women and their newborns, adults age 65 and older, and people with weakened immune systems are more likely to get sick with listeriosis.
If you develop symptoms of a Listeria infection after eating deli-sliced products, contact a healthcare provider and tell them you ate deli-sliced products. This is especially important if you are pregnant, age 65 or older, or have a weakened immune system.
If you have eaten deli-sliced products and do not have any symptoms of a Listeria infection, most experts believe that tests or treatment are not needed, even for people who have a higher chance of Listeria infection.
Listeria bacteria can survive at very low temperatures and can spread easily to other foods and surfaces. Consumers should clean refrigerators, kitchen countertops, utensils, and other surfaces that touch deli-sliced products.
Note to journalists (if there are any left): Don’t reprint PR fluff like it’s news and don’t bury the lede.
“A good way to test your food is also a simple way: give it a sniff,” says Roni Neff, PhD. “If the date says ‘best by’ and it looks and smells okay, it’s probably okay to eat.”
Probably is not good enough, and smell is a lousy indicator of food safety.
A new survey examining U.S. consumer attitudes and behaviors related to food date labels found widespread confusion, leading to unnecessary discards, increased waste and food safety risks. The survey analysis was led by researchers at the Johns Hopkins Center for a Livable Future (CLF), which is based at the Johns Hopkins Bloomberg School of Public Health.
This study calls attention to the issue that much food may be discarded unnecessarily based on food safety concerns, though relatively few food items are likely to become unsafe before becoming unpalatable. Clear and consistent date label information is designed to help consumers understand when they should and should not worry.
Among survey participants, the research found that 84 percent discarded food near the package date” occasionally” and 37 percent reported that they “always” or “usually” discard food near the package date. Notably, participants between the ages of 18 to 34 were particularly likely to rely on label dates to discard food. More than half of participants incorrectly thought that date labeling was federally regulated or reported being unsure. In addition, the study found that those perceiving labels as reflecting safety and those who thought labels were federally regulated were more willing to discard food.
New voluntary industry standards for date labeling were recently adopted. Under this system, “Best if used by” labels denote dates after which quality may decline but the products may still be consumed, while “Use by” labels are restricted to the relatively few foods where safety is a concern and the food should be discarded after the date. Previously, all labels reflected quality and there was no safety label.
Neff and colleagues found that among labels assessed, “Best if used by” was most frequently perceived as communicating quality, while “use by” was one of the top two perceived as communicating safety. But many had different interpretations.
Lead author, Roni Neff, PhD, who directs the Food System Sustainability Program with the CLF and is an assistant professor with the Bloomberg School’s Department of Environmental Health and Engineering said, “The voluntary standard is an important step forward. Given the diverse interpretations, our study underlines the need for a concerted effort to communicate the meanings of the new labels. We are doing further work to understand how best to message about the terms.”
How best to message about the terms? Maybe use language properly.
Using an online survey tool, Neff and colleagues from Harvard University and the National Consumers League assessed the frequency of discards based on date labels by food type, interpretation of label language and knowledge of whether date labels are regulated by the federal government. The survey was conducted with a national sample of 1,029 adults ages 18 to 65 and older in April of 2016. Recognizing that labels are perceived differently on different foods, the questions covered nine food types including bagged spinach, deli meats and canned foods.
When consumers perceived a date label as an indication of food safety, they were more likely to discard the food by the provided date. In addition, participants were more likely to discard perishable foods based on labels than nonperishables.
But dates can be a lousy indicator: I’ve got deli meat in the fridge with a use by label about 2 weeks from now, yet once that package is opened, the stuff is good for 2-4 days. Publix gets it right.
Smell, like color, is a lousy indicator of food safety.
The show opens with a discussion about privacy, whether you should cover the microphone on your computer, or how you can scare your kids using Alexa. The guys talked briefly about what they’re watching, Ben’s trip to Athens Georgia, and celebrity feet. From there the show moves into listener feedback talking about the safety of eating Canadian seaweed. Listener feedback makes a interesting segue into failure, and the things we can learn from it. The show returns to listener feedback with a discussion about citrus safety and infused water. For some reason Don wants to talk about smoke detectors, before returning again to listener feedback and “Contamination Corner”, and ways to learn about stuff you don’t know about (like filibusters). Ben and Don talk about an interview that Don did for Cooking Light, before Don wants to talk about fixing his broken software. Ben ends the show with a long discussion regarding safe cooking directions for frozen vegetables, and why no one can agree.
Listeria monocytogenes is a foodborne pathogen that disproportionally affects pregnant females, older adults, and immunocompromised individuals. Using U.S. Foodborne Diseases Active Surveillance Network (FoodNet) surveillance data, we examined listeriosis incidence rates and rate ratios (RRs) by age, sex, race/ethnicity, and pregnancy status across three periods from 2008 to 2016, as recent incidence trends in U.S. subgroups had not been evaluated. The invasive listeriosis annual incidence rate per 100,000 for 2008–2016 was 0.28 cases among the general population (excluding pregnant females), and 3.73 cases among pregnant females.
For adults ≥70 years, the annual incidence rate per 100,000 was 1.33 cases. No significant change in estimated listeriosis incidence was found over the 2008–2016 period, except for a small, but significantly lower pregnancy-associated rate in 2011–2013 when compared with 2008–2010. Among the nonpregnancy-associated cases, RRs increased with age from 0.43 (95% confidence interval: 0.25–0.73) for 0- to 14-year olds to 44.9 (33.5–60.0) for ≥85-year olds, compared with 15- to 44-year olds. Males had an incidence of 1.28 (1.12–1.45) times that of females. Compared with non-Hispanic whites, the incidence was 1.57 (1.18–1.20) times higher among non-Hispanic Asians, 1.49 (1.22–1.83) among non-Hispanic blacks, and 1.73 (1.15–2.62) among Hispanics. Among females of childbearing age, non-Hispanic Asian females had 2.72 (1.51–4.89) and Hispanic females 3.13 (2.12–4.89) times higher incidence than non-Hispanic whites. We observed a higher percentage of deaths among older patient groups compared with 15- to 44-year olds.
This study is the first characterizing higher RRs for listeriosis in the United States among non-Hispanic blacks and Asians compared with non-Hispanic whites. This information for public health risk managers may spur further research to understand if differences in listeriosis rates relate to differences in consumption patterns of foods with higher contamination levels, food handling practices, comorbidities, immunodeficiencies, health care access, or other factors.
Differences among incidence rates of invasive Listeriosis in the U.S. FoodNet population by age, sex, race/ethnicity, and pregnancy status, 2008–2016
Pohl, A. M., Pouillot, R., Bazaco, M. C., Wolpert, B. J., Healy, J. M., Bruce, B. B., . . . Doren, J. M. (2019).
On December 1, 2017, PulseNet, the U.S. Centers for Disease Control’s molecular subtyping network for foodborne disease surveillance, identified a cluster of three Listeria monocytogenes clinical isolates with indistinguishable pulsed-field gel electrophoresis (PFGE) pattern combinations. These isolates were closely related to one another by whole-genome multilocus sequence typing within three allele differences (range = 0–3 alleles), indicating that the infections were likely from the same source.
CDC, the Food and Drug Administration (FDA), and state and local health departments initiated a multistate investigation. An outbreak case of listeriosis was defined as an infection with L. monocytogenes, with an isolate that was indistinguishable by PFGE and closely related by whole-genome multilocus sequence typing to the outbreak strain isolated during October–December 2017.
The cases corresponding to the three isolates were identified in Illinois, Iowa, and Michigan. Isolation dates ranged from October 15, 2017, to October 29, 2017. Patients ranged in age from 55 to 71 years (median = 69 years), and all three patients were male. All patients were hospitalized for listeriosis; no deaths were reported. PulseNet was queried routinely for new isolate matches during the investigation, and no additional cases were identified.
Interviews were conducted with all three patients or their surrogates using the standard Listeria Initiative questionnaire (1), which asks about a variety of foods consumed in the month preceding illness onset. Grocery store receipts were collected for the patient in Michigan. Review of reported exposures indicated that all three patients had consumed prepackaged caramel apples purchased from retail establishments in the month preceding illness onset. A case-case analysis was performed comparing exposure frequencies for all food items included in the Listeria Initiative questionnaire for the three outbreak-associated cases with exposure frequencies for 186 sporadic cases of listeriosis from the same states reported to CDC since 2006. Caramel apple consumption was significantly higher among patients included in the outbreak, compared with that among patients with sporadic illnesses (odds ratio = 21.7; 95% confidence interval = 2.3–infinity). None of the interviewed patients had leftover caramel apples in their home for testing.
State and local officials collected records at two of the three retail locations where caramel apples had been purchased. All three retailers sold the same brand of caramel apples (brand A). The product was packaged in a plastic clamshell containing three caramel apples, each on a stick. Caramel apples were seasonal products that were only available for a short period in the fall at two of the retail locations. However, the retail location where the Illinois patient purchased caramel apples had the product in stock at the time of the investigation. Eight packages of caramel apples were collected for testing by the Illinois Department of Public Health, but L. monocytogenes was not detected in any samples. It was not known whether the tested caramel apples were from the same lots as those consumed by the ill persons in this outbreak.
During an inspection at the caramel apple production facility, FDA reviewed records and practices and collected environmental samples for testing. No significant food safety concerns were observed. None of the environmental swabs yielded L. monocytogenes. Environmental swabs collected at a single whole apple supplier yielded L. monocytogenes, but it was not the outbreak strain. Traceback activities did not implicate a specific lot or supplier of whole apples used in brand A caramel apple production during the period of interest.
No additional outbreak-associated illnesses were identified during the investigation. In light of the limited shelf life of the product (reported by the production facility to be 15 days), it was unlikely that caramel apples consumed by ill persons in this outbreak would have still been available for purchase or in persons’ homes at the time of the investigation. Because there was no evidence to suggest an ongoing risk to the public, no public warning was issued by federal or state agencies.
Although the outbreak strain of L. monocytogenes was not isolated from caramel apples or their production environment, the epidemiologic evidence indicated that caramel apples were the suspected vehicle in this outbreak. All outbreak-associated ill persons consumed a specific brand of a relatively uncommon food product in the month before their illness onset, and all were infected with indistinguishable L. monocytogenes strains. Caramel apples were previously implicated in a large multistate outbreak of listeriosis during 2014–2015, caused by contamination of whole apples (2). Ready-to-eat food processors, including those that make caramel apples, could consider the introduction and persistence of L. monocytogenes in food production environments as a potential hazard and mitigate that risk through appropriate environmental monitoring and preventive controls (3). Further research into the control of L. monocytogenes in fresh produce, including fresh apples, might help identify prevention strategies to reduce or eliminate the pathogen in some ready-to-eat foods.
Notes from the field: Outbreak of listeriosis likely associated with prepackaged caramel apples
Jessica R. Marus, MPH1; Sally Bidol, MPH2; Shana M. Altman3; Oluwakemi Oni, MPH4; Nicole Parker-Strobe, MPH2; Mark Otto, MSPH5; Evelyn Pereira, MPH5; Annemarie Buchholz, PhD5; Jasmine Huffman1,6; Amanda R. Conrad, MPH1; Matthew E. Wise, PhD1
1Division of Foodborne, Waterborne, and Environmental Diseases, National Center for Emerging and Zoonotic Infectious Diseases, CDC; 2Michigan Department of Health and Human Services; 3Illinois Department of Public Health; 4Iowa Department of Public Health; 5Food and Drug Administration, Silver Spring, Maryland; 6Oak Ridge Institute for Science and Education, Oak Ridge, Tennessee.
All authors have completed and submitted the ICMJE form for disclosure of potential conflicts of interest. No potential conflicts of interest were disclosed.
On Oct. 14, 2018, McCain Foods initiated a creeping crawling outbreak of processing vegetables from its Colton Calif. plant that lasted six weeks.
Now that plant has been closed.
Early in Jan., 2019, Sam Bloch of New Food Economy wrote that the Colton facility produced commercial ingredients—the invisible mortar of the food system.
You might not know McCain, but you’ve probably eaten its food. The multi-billion-dollar foodservice corporation, based in Toronto, Ontario (that’s in Canada), manufactures frozen foods—primarily potatoes, but also fruits and vegetables, pizzas, juices, and various oven meals—in 53 plants around the world.
(Bloch writes that McCain brags that one in every four French fries eaten globally is McCain. Bloch could have done a little digging and found that the McCain family are an on-going soap-opera of Machiavellian proportions, in Canadian terms, rivalled only by the Seagram family who made their fortune running booze to the U.S. during U.S. Prohibition. Oh, and the McCain family also killed genetically-engineered Bt potatoes which would have offered some chemical relief to the steams and environment, especially in Eastern Canada, but that’s another story. Back to the veggies).
Combined, the McCain recalls will affect over 99 million pounds of food.
Now Bloch writes McCain has closed its Colton, California plant, which had processed the vegetables, including chopped onions, peppers, and roasted corn, and sold them as ingredients to commercial kitchens and food manufacturers all over the country. The recalls spread to what seemed like every aisle of the supermarket, from prepackaged salads at Whole Foods and Trader Joe’s to cheese dips and frozen Kashi grain bowls. The total amount of product affected exceeds 100 million pounds, making it the largest recall of 2018, and perhaps of recent memory.
McCain announced the plant’s closure on January 11, which, according to a statement from the company, will result in layoffs for 100 employees. In an email to The New Food Economy, Andrea Davis, a McCain spokeswoman confirmed the recall influenced the decision to close the plant,but said there were other factors involved.
“The product mix produced at the Colton facility does not support the changing needs of our portfolio,” Davis wrote. “While the recent recall was one consideration, the decision to permanently close the facility was ultimately a business decision.”
It is not clear exactly when the plant will be closed, and McCain representatives could not be reached for further comment by press time.
The facility in question had a history of food safety violations.
The agribusiness program Goldberg developed in 1955 continues to bring business leaders and policy makers from around the world together each year. Throughout his tenure, Ray has written over 100 articles and 24 books on the business of agriculture, including his very latest, Food Citizenship: Food System Advocates in an Era of Distrust.
He was interviewed by podcast host, Brian Kenny: Did you coin the term agribusiness?
Ray Goldberg: I did, together with John Davis. He was the Assistant Secretary of Agriculture under Eisenhower, and he became the first head of the (HBS) Agribusiness Program.
Brian Kenny: The case cites examples of foodborne illness outbreaks in the US. We’re coming on the heels of the recent romaine lettuce issue in the US, which has now occurred, I think, twice in the last few months.
Ray Goldberg: I can describe the romaine lettuce [event], because I talked to the produce manager this morning, and he tells me the cost to the industry was $100 million dollars.
The problem is that romaine lettuce itself, when cold temperatures occur, begins to blister, which make it more susceptible to listeria. When they tried to find the location of that listeria, it came from a dairy herd about 2,000 feet away from where that lettuce was grown. We have a rule that 1,200 feet is far enough, but they actually found listeria a mile away from where that lettuce was concerned, so he feels very strongly that they have to change the rules.
(They seem to be confusing Listeria with E.coli O157 in Romaine, but that’s Haaaaaaaaarvard.)
Brian Kenny: Which gets to another issue that the case raises, which is has the industry done well enough trying to regulate itself? What are some of the things the industry has tried to do?
Ray Goldberg: Under Danny Wegman’s leadership—he was the person in charge of food safety of the Food Marketing Institute that really looked at the whole industry—he got several members of the industry to sit down and create new rules with the FDA, the EPA, the USDA, and CDC, all of them saying we have to have better rules. Produce, as you know in the case, is the most valuable part of a supermarket but also the most susceptible to problems.
Brian Kenny: This gets a little bit to the topic of your book, Food System Advocates in an Era of Distrust. [What[ are the big ideas coming out of your book?
Ray Goldberg: The big ideas are two-fold, that the kind of men and women in the industry have changed from commodity handlers and bargaining as to how cheap they can buy something, or how expensive they can make something, to finally realizing that they have to be trusted. And because they have to be trusted, they have to start working together to create that trust. In addition to that, they realize that the private, public and not-for-profit sectors really need to work together. That’s why I tried to write a book to give people an inkling of the kind of men and women in this industry who really are the change-makers, who are changing it to a consumer-oriented, health-oriented, environmentally-oriented, economic development-oriented industry.
Now, over three years since residents of Ontario (that’s in Canada) began reporting illnesses from Listeria in pasteurized chocolate milk produced at a dairy in Georgetown, Ontario, investigators have gotten around to saying just how many people got sick.
According to health-types writing in Emerging Infectious Disease, 11 case-patients had an onset date during November 14, 2015–February 14, 2016. Onset dates ranged from April 11 to June 20, 2016, for 21 case-patients in the second wave; the remaining 2 case-patients were outliers. Median age was 73 years (range <1 years–90 years). More than half of the case-patients were female (20/34, 59%). Hospitalizations occurred for 32 (94%) case-patients, and 4 deaths (12%) were reported.
In Ontario, local public health professionals complete the national invasive listeriosis questionnaire and collect food samples. We conducted a case–case analysis by using Ontario case-patients listed in the national listeriosis database as controls. We used a variety of methods to support hypothesis generation, including supplemental questionnaires, centralized interviewing, and reviewing purchase records collected through shoppers’ loyalty card programs. A meeting was also held with representatives from a grocery chain that was common for case-patients (retail chain A) for insights into possible sources.
PFGE and whole-genome sequencing were performed at the Public Health Ontario Laboratory, in accordance with PulseNet Canada protocols (Table). Food safety investigations, including targeted retail sampling, were conducted by the Canadian Food Inspection Agency and Ontario Ministry of Agriculture and Food and Rural Affairs. Laboratory analyses of food samples were conducted by the Canadian Food Inspection Agency and the Public Health Ontario Laboratory.
Several hypotheses were generated during the course of this outbreak. In the first wave, a concurrent listeriosis outbreak associated with leafy greens was ongoing in the United States and Canada. However, product testing did not establish a relationship between the 2 outbreaks. Cheddar cheese was also suspected, but a food safety investigation, including sampling at the manufacturer, did not support a link to this outbreak (6,7). Although leafy greens and cheddar cheese were ruled out, 1 commonality remained; shopping at retail chain A was reported frequently by case-patients.
A second wave began in April 2016 in which 10 of 17 case-patients reported consuming coleslaw. Six case-patients ate coleslaw from the same manufacturer, which supplied retail chain A and a fast food restaurant chain. However, the food safety investigation, including sampling at the manufacturer and supplier, did not support this hypothesis.
On May 24, 2016, L. monocytogenes isolated from expired bagged chocolate milk collected from the home of 1 case-patient was confirmed to have the outbreak strain PFGE pattern. Fluid milk in Canada is often sold in plastic bags. In this instance, the outer packaging, which is the only area that contains the brand name, was discarded. Thus, the brand name was uncertain, and efforts were undertaken to confirm the source of the chocolate milk. Because the proxy of the case-patient reported purchasing brand B milk, samples of brand B chocolate and white milk were collected from retail for testing. Brand B was the main brand of chocolate milk sold by retail chain A, and it is distributed only in Ontario.
Although the hypothesis-generating questionnaire used stipulated milk, with flavored milk as a prompt, chocolate milk was not specified, and as a result this type of milk might have been underreported. Exposure to pasteurized milk was reported by 60% of case-patients in the first wave compared with 76% of controls. Thus, milk was not originally pursued as a source. However, this new positive isolate led to re-interviewing of case-patients from the second wave and resulted in 9 (75%) of 12 case-patients reporting consuming brand B when asked specifically about chocolate milk.
On June 3, a retail sample of brand B chocolate milk was confirmed positive for L. monocytogenes. This finding led to a class I recall of 1 lot of brand B chocolate milk. On June 5, the recall was expanded to all lots of brand B chocolate milk processed at that facility because of the result of extensive retail sampling. Isolates from the original sample and 3 subsequent positive samples of chocolate milk matched the outbreak strain by PFGE and whole-genome sequencing. No white milk samples were positive for L. monocytogenes.
Environmental sampling at the manufacturer confirmed the presence of the outbreak strain within a post-pasteurization pump dedicated to chocolate milk and on nonfood contact surfaces. This post-process contamination of the chocolate milk line was believed to be the root cause of the outbreak. A harborage site might have been introduced by a specific maintenance event or poor equipment design. The equipment was subsequently replaced, and corrective measures were implemented to prevent reoccurrence. Chocolate milk production was resumed after vigorous testing for L. monocytogenes under regulatory oversight.
This outbreak lasted 7 months and resulted in 34 confirmed listeriosis case-patients. Discovering the cause of this listeriosis outbreak was challenging because pasteurized chocolate milk is a commonly consumed product. Although there have been previous outbreaks outside Canada caused by chocolate milk, pasteurized milk products are generally not expected to be the source. This outbreak highlights that even pasteurized products can be contaminated by and support the proliferation of L. monocytogenes when contamination is introduced post-pasteurization. The possibility of post-processing contamination indicates an ongoing need for regulatory oversight and robust quality assurance processes, which include routine sampling of the environment and finished products.
Brand B chocolate milk is a widely distributed product in Ontario, and contamination of this product could have resulted in >34 case-patients. It is possible that a lower number of case-patients were reported because chocolate milk may primarily be consumed by younger, healthier persons, in whom invasive listeriosis is less likely to develop. Another possible explanation is that the contamination in the milk appeared to be intermittent, with some samples testing positive while others tested negative. As such, careful attention should be given to equipment design and maintenance programs, as harborage sites could result in recurring contamination that goes undetected by routine monitoring. Targeted retail and environmental sampling was instrumental in identifiying the root cause in the facility and the breadth of potentially implicated products in the marketplace. Thus, this type of sampling should be considered during outbreak investigations.
Ultimately, the implicated product was determined on the basis of testing of food items obtained from the home of 1 case-patient. This finding highlights the necessity of obtaining a thorough food history and collecting and testing available samples of food that case-patients consumed during the incubation period. In Canada, where bagged milk is common, labeling of the inner and outer bags with the brand name would facilitate product identification by consumers. This recommendation could extend to other food products in North America (e.g., frozen hamburger patties) that have multiple layers of packaging.
That is a lucid, thought provoking summary of a complex foodborne outbreak, fraught with uncertainties.
When the Canadian Food Inspection Agency announced the recall on June 4, 2016, Chapman wrote it up for the blog, reminiscing about his childhood innocence in southern Ontario, and noted, as has become the pattern, that CFIA reports recalls, but it’s up to PHAC or provincial health ministries to identify the number of sick people. As far as I can tell, no public statement about illnesses was ever made, until now.
What the fuck do these people do, especially the communication hacks? Do they have a responsibility to the public? Why didn’t epidemiology count and a public warning issued rather than waiting for a positive sample in an unopened package, which has apparently become the Canadian standard for going public?
If that’s the standard, that sucks.
Listeria monocytogenes associated with pasteurized chocolate milk, Ontario, Canada
Emerging Infectious Diseases vol. 25 no. 3
Heather Hanson , Yvonne Whitfield, Christina Lee, Tina Badiani, Carolyn Minielly, Jillian Fenik, Tony Makrostergios, Christine Kopko, Anna Majury, Elizabeth Hillyer, Lisa Fortuna, Anne Maki, Allana Murphy, Marina Lombos, Sandra Zittermann, Yang Yu, Kristin Hill, Adrienne Kong, Davendra Sharma, and Bryna Warshawsky
In an investigation of a listeriosis outbreak in Ontario, Canada, during November 2015–June 2016, Public Health Ontario identified pasteurized chocolate milk as the source. Because listeriosis outbreaks associated with pasteurized milk are rare in North America, these findings highlight that dairy products can be contaminated after pasteurization.
The U.S. Centers for Disease Control reports that an outbreak of Listeria monocytogenes infections linked to pork products produced by Long Phung Food Products appears to be over.
On November 20, 2018, 165368 C. Corporation of Houston, Texas, doing business as Long Phung Food Products, recalled ready-to-eat pork products because they might have been contaminated with Listeria bacteria.
Do not eat, sell, or serve recalled products from Long Phung Food Products.
Retailers should clean and sanitize deli slicers and other areas where recalled pork products were prepared, stored, or served. Follow the manufacturer’s recommendations for sanitizer strength and application to ensure it is effective.
If you develop symptoms of a Listeria infection after eating recalled pork products, contact a healthcare provider and tell them you ate recalled pork products. This is especially important if you are pregnant, age 65 or older, or have a weakened immune system.
As of January 29, 2019, this outbreak appears to be over.
Four people infected with the outbreak strain of Listeria monocytogenes were reported from four states.
Listeria specimens from ill people were collected from July 1, 2017, to October 24, 2018.
Four people were hospitalized. No deaths were reported.
Cornell University scientists have developed a computer program, Environmental Monitoring With an Agent-Based Model of Listeria (EnABLe), to simulate the most likely locations in a processing facility where the foodborne pathogen Listeria monocytogenes might be found. Food safety managers may then test those areas for the bacteria’s presence, adding an important tool to prevent food contamination and human exposure to the pathogen through tainted food.
The computer model, which is described in the Jan. 24 issue of Scientific Reports, has the potential to be modified for a wide range of microbes and locations.
“The goal is to build a decision-support tool for control of any pathogen in any complex environment,” said Renata Ivanek, associate professor in the Department of Population Medicine and Diagnostic Sciences and senior author of the paper. The study was funded by the Frozen Food Foundation through a grant to Martin Wiedmann, professor of food science, who is also a co-author of the paper.
The researchers, including first author Claire Zoellner, a postdoctoral research associate in Ivanek’s lab, want to eventually apply the framework to identifying contamination from pathogens that cause hospital-acquired infections in veterinary hospitals or E. coli bacteria in fruit and vegetable processing plants.
Food safety professionals at processing facilities keep regular schedules for pathogen testing. They rely on their own expertise and knowledge of the building to determine where to swab for samples.
“Whenever we have an environment that is complex, we always have to rely on expert opinion and general rules for this system, or this company, but what we’re trying to offer is a way to make this more quantitative and systematic by creating this digital reality,” Ivanek said.
For the system to work, Zoellner, Ivanek and colleagues entered all relevant data into the model – including historical perspectives, expert feedback, details of the equipment used and its cleaning schedule, the jobs people do, and materials and people who enter from outside the facility.
“A computer model like EnABLe connects those data to help answer questions related to changes in contamination risks, potential sources of contamination and approaches for risk mitigation and management,” Zoellner said.
“A single person could never keep track of all that information, but if we run this model on a computer, we can have in one iteration a distribution of Listeria across equipment after one week. And every time you run it, it will be different and collectively predict a range of possible outcomes,” Ivanek said.
The paper describes a model system that traces Listeria species on equipment and surfaces in a cold-smoked salmon facility. Simulations revealed contamination dynamics and risks for Listeria contamination on equipment surfaces. Furthermore, the insights gained from seeing patterns in the areas where Listeria is predicted can inform the design of food processing plants and Listeria-monitoring programs. In the future, the model will be applied to frozen food facilities.