Listeria monocytogenes is a ubiquitous pathogen with a high mortality rate that can become persistent in the retail food environment, says Janet Buffer, MPH, of the Center for Foodborne Illness Research and Prevention, Ohio State University. During her presentation “Listeria monocytogenes and sanitation in the retail environment,” at the “Food Safety Hazards Series” virtual event, she discussed areas in retail food service environments most likely to harbor the pathogen as well as the best-proven methods to reduce the prevalence of listeria in your facility.
Areas that are more likely to harbor listeria monocytogenes in the retail food environment include:
Cracks and crevices in the floor
The floor/wall juncture, especially under sinks
On touchpoints of cooler handles and deli slicers
In front of deep fryers
In front of deli slicers and on slicer blades
Areas where raw chicken is stored or transported
“Listeria monocytogenes is hardy. It tolerates salt, grows in cold environments and is moderately resistant to acids,” said Buffer. “It is also ubiquitous. We find it in soil, water, silage, manure and sewage. We bring it in on our shoes. We can carry it on our clothes, and it can become a persistent pathogen in our retail spaces.”
A recent study by Briana C. Britton, et al, published in Food Control Journal, identified the most effective sanitation and customer service strategies correlated with lower listeria prevalence in retail delicatessens. These include:
When the deli is cleaned two-to-three hours/day
Changing gloves after touching nonfood surfaces
Keeping sanitation records
Using foam to clean and sanitize
“All chemicals work and all work very well,” said Buffer. “But, they must be used at the correct concentrations and they will require some elbow grease.”
The Interagency Food Safety Analytics Collaboration (IFSAC) has published its 2022–2023 Interim Strategic Plan, placing continued emphasis on foodborne illness source attribution for Salmonella, E. coli O157:H7, Listeria monocytogenes and Campylobacter. Over the next year, IFSAC will address several short-term goals surrounding improvement of methods to evaluate and identify foodborne illness source attribution through the use of outbreak and non-outbreak-associated disease data, and continued collaboration with external partners in an effort to boost data access and capabilities. The group will be targeting several efforts in the coming year, including:
Analysis of trends related to foodborne disease outbreak-associated illnesses over the past two decades, with a subsequent peer-reviewed journal article that reveals results.
Development and improvement of machine-learning methods used to predict food sources of illnesses that have an unknown source. WGS will be used to compare Salmonella isolates of known and unknown sources.
Collaboration with FoodNet when assessing key food sources for sporadic Salmonella Enteritidis and Campylobacter illnesses. The group will develop case-control studies using specific FoodNet data.
Formed in 2011, IFSAC is a partnership between FDA, FSIS and the CDC that seeks to strengthen federal interagency efforts and maximize use of food safety data collection, analysis and use. During 2022–2023, IFSAC will publish its yearly reports on foodborne illness source attribution for the previously mentioned priority pathogens.
Dole Fresh Vegetables, Inc. has now issued a voluntary recall of Dole-branded and private label packaged salads processed at its Springfield, OH (product ID lot code “W” and “Best if Used By” date December 22, 2021–January 9, 2022) and Soledad, CA production facilities containing iceberg lettuce.
–END UPDATE —
The FDA and CDC are investigating a multistate outbreak of Listeria monocytogenes illnesses linked to Fresh Express Packaged Salad and Dole Packaged Salad.
Last month Dole Fresh Vegetables issued a voluntary recall for salads processed at its facilities in Bessemer City, NC and Yuma, AZ due to the health risk. The company also temporarily suspended operations at both facilities. The brand names in which the salads were sold under include Dole, Kroger, Lidl, Little Salad Bar, Marketside, Naturally Better, Nature’s Promise and Simply Nature. The products have “Best if Used By” dates between November 30, 2021 and January 8, 2022.
The agencies’ investigation of Fresh Express Packaged Salad resulted in the company stopping production at its Streamwood, IL facility. It also initiated a recall of certain varieties of its branded and private-label salads that were produced at this facility.
The FDA’s investigation into the Listeria monocytogenes outbreak linked to both Dole and Fresh Express is ongoing. Thus far, no deaths linked to the outbreak have been reported.
Baker issued a recall of its Baker Farms, Kroger, & SEG Grocers brand names of kale following a customer notification of Listeria monocytogenes contamination. The 1-lb plastic bags of kale have best buy dates of 09-18-2021 and were distributed to retail stores in Alabama, Arkansas, Florida, Georgia, Louisiana, Missouri, Mississippi, North Caroline, New York and Virginia. Thus far no consumers have reported illness.
Tyson Foods, Inc. is recalling 8,492,832 pounds of ready-to-eat (RTE) chicken products over concerns that the product may be adulterated with Listeria monocytogenes. The Class I recall affects frozen, fully cooked chicken products that were produced between December 26, 2020 and April 13, 2021, and shipped nationwide to retailers and facilities that include hospitals, nursing homes, restaurants, schools and Department of Defense locations. The recalled products bear establishment number “EST. P-7089” on the product bag or inside the USDA mark of inspection.
The FSIS website lists all products affected by the recall—which includes diced chicken, frozen, fully cooked chicken strips, diced chicken, chicken used for fajitas chicken wing sections, and pizza with fully cooked chicken.
–UPDATE March 9, 2021 — Today the FDA confirmed that the recalled cheeses were also distributed to Rhode Island. “States with confirmed distribution now include: AL, CT, FL, GA, IA, IL, IN, KS, KY, MA, MD, MI, MN, MO, MS, NC, NJ, NY, NE, OH, PA, RI, SC, TN, VA, and WI.”
–UPDATE February 24, 2021 — FDA has expanded its warning related to El Abuelito Cheese to include all cheese branded by the company “until more information is known”.
A multistate outbreak of Listeria monocytogenes has been linked to Hispanic-style fresh and soft cheeses produced by El Abuelito Cheese, Inc. As a result, the company has recalled all Questo Fresco products with sell by dates through March 28 (032821).
Join Food Safety Tech on April 15 for the complimentary Food Safety Hazards Series: Listeria Detection, Mitigation, Control & Regulation“As the FDA stated, about this outbreak investigation, the Connecticut Department of Public Health collected product samples of El Abuelito-brand Hispanic-style fresh and soft cheeses from a store where a sick person bought cheeses. Sample analysis showed the presence of Listeria monocytogenes in samples of El Abuelito Queso Fresco sold in 10 oz packages, marked as Lot A027 with an expiration date of 02/26/2021,” the company stated in an announcement posted on FDA’s website. “Samples are currently undergoing Whole Genome Sequencing (WGS) analysis to determine if the Listeria monocytogenes found in these samples is a match to the outbreak strain. At this time, there is not enough evidence to determine if this outbreak is linked to El Abuelito Queso Fresco.”.
The recalled products were distributed to Connecticut, Maryland, New Jersey, North Carolina, New York, Pennsylvania and Virginia. Thus far seven people, all of whom have been hospitalized, have fallen ill.
FDA recommends that consumers, restaurants and retailers do not consume, sell or serve any of the recalled cheeses. The agency also states that anyone who purchased of received the recalled products use “extra vigilance in cleaning and sanitizing any surfaces and containers that may have come in contact with these products to reduce the risk of cross-contamination.”
On October 29, 2020 attend the Food Safety Consortium Virtual episode on Listeria Detection, Mitigation and ControlThe CDC and USDA are investigating a multistate outbreak of Listeria monocytogenes that has sent 10 people to the hospital and resulted in one death. The outbreak, which as of October 22 has reported illnesses in Florida (1), Massachusetts (7) and New York (2), has been linked to Italian-style deli meats such as salami, mortadella and prosciutto. Currently no specific deli meat or common supplier has been identified.
CDC, FSIS and other public health officials are using PulseNet to identify any illnesses that could be linked to the outbreak. The following is a link to the CDC’s map of reported cases by state.
Remember the 2015 Listeria outbreak linked to Blue Bell Creameries? The outbreak led to three deaths and 10 illnesses between January 2010 and January 2015. On Thursday the Department of Justice ordered the company to pay $17.25 million in criminal penalties for shipping contaminated products linked to that outbreak. The sentence, enforced by U.S. District Judge Robert Pitman (Austin, Texas), is the largest fine and forfeiture ever imposed in a conviction involving a food safety case.
“American consumers must be able to trust that the foods they purchase are safe to eat,” stated – Acting Assistant Attorney General Jeffrey Bossert Clark, Justice Department’s Civil Division in an agency news release. “The sentence imposed today sends a clear message to food manufacturers that the Department of Justice will take appropriate actions when contaminated food products endanger consumers.”
In May 2020 Blue Bell pleaded guilty to two misdemeanor counts of distributing adulterated ice cream. The following is an excerpt from the Department of Justice news release:
“The plea agreement and criminal information filed against Blue Bell allege that the company distributed ice cream products that were manufactured under insanitary conditions and contaminated with Listeria monocytogenes, in violation of the Food, Drug and Cosmetic Act. According to the plea agreement, Texas state officials notified Blue Bell in February 2015 that samples of two ice cream products from the company’s Brenham, Texas factory tested positive for Listeria monocytogenes, a dangerous pathogen that can lead to serious illness or death in vulnerable populations such as pregnant women, newborns, the elderly, and those with compromised immune systems. Blue Bell directed its delivery route drivers to remove remaining stock of the two products from store shelves, but the company did not recall the products or issue any formal communication to inform customers about the potential Listeria contamination. Two weeks after receiving notification of the first positive Listeria tests, Texas state officials informed Blue Bell that additional state-led testing confirmed Listeria in a third product. Blue Bell again chose not to issue any formal notification to customers regarding the positive tests. Blue Bell’s customers included military installations.”
By Benjamin A. Katchman, Ph.D., Michael E. Hogan, Ph.D., Nathan Libbey, Patrick M. Bird No Comments
The Golden Age of Bacteriology: Discovering the Unknown in a Farm-to-Market Food Supply.
The last quarter of the 19th Century was both horrific and exciting. The world had just emerged from four decades of epidemic in cholera, typhoid fever and other enteric diseases for which no cause was known. Thus, the great scientific minds of Europe sought to find understanding. Robert Koch integrated Pasteur’s Germ Theory in 1861 with the high technology of the day: Mathematical optics and the first industrialized compound microscopes (Siebert, Leiss, 1877), heterocycle chemistry, high-purity solvents (i.e., formaldehyde), availability of engineered glass suitable as microscope slides and precision-molded parts such as tubes and plates in 1877, and industrialized agar production from seaweed in Japan in 1860. The enduring fruit of Koch’s technology integration tour de force is well known: Dye staining of bacteria for sub-micron microscopy, the invention of 13 cm x 1 cm culture tubes and the invention of the “Petri” dish coupled to agar-enriched culture media. Those technologies not only launched “The Golden Age of Bacteriology” but also guided the entire field of analytical microbiology for two lifetimes, becoming bedrock of 20th Century food safety regulation (the Federal Food, Drug and Cosmetic Act in 1938) and well into the 21st century with FSMA.
Learn more about technologies in food safety testing at the Food Labs / Cannabis Labs Conference | June 2–4, 2020 | Register now!Blockchain Microbiology: Managing the Known in an International Food Supply Chain.
If Koch were to reappear in 2020 and were presented with a manual of technical microbiology, he would have little difficulty recognizing the current practice of cell fixation, staining and microscopy, or the SOPs associated with fluid phase enrichment culture and agar plate culture on glass dishes (still named after his lab assistant). The point to be made is that the analytical plate culture technology developed by Koch was game changing then, in the “farm-to-market” supply chain in Koch’s hometown of Berlin. But today, plate culture still takes about 24 to 72 hours for broad class indicator identification and 48 to 96 hours for limited species level identification of common pathogens. In 1880, life was slow and that much time was needed to travel by train from Paris to Berlin. In 2020, that is the time needed to ship food to Berlin from any place on earth. While more rapid tests have been developed such as the ATP assay, they lack the speciation and analytical confidence necessary to provide actionable information to food safety professionals.
It can be argued that leading up to 2020, there has been an significant paradigm shift in the understanding of microbiology (genetics, systems based understanding of microbial function), which can now be coupled to new Third Industrial Age technologies, to make the 2020 international food supply chain safer.
We Are Not in 1880 Anymore: The Time has Come to Move Food Safety Testing into the 21st Century.
Each year, there are more than 48 million illnesses in the United States due to contaminated food.1 These illnesses place a heavy burden on consumers, food manufacturers, healthcare, and other ancillary parties, resulting in more than $75 billion in cost for the United States alone.2 This figure, while seemingly staggering, may increase in future years as reporting continues to increase. For Salmonella related illnesses alone, an estimated 97% of cases go unreported and Listeria monocytogenes is estimated to cause about 1,600 illnesses each year in the United States with more than 1,500 related hospitalizations and 260 related deaths.1,3 As reporting increases, food producers and regulatory bodies will feel an increased need to surveil all aspects of food production, from soil and air, to final product and packaging. The current standards for pathogenic agriculture and environmental testing, culture-based methods, qPCR and ATP assays are not able to meet the rapid, multiplexed and specificity required to meet the current and future demands of the industry.
At the DNA level, single cell level by PCR, high throughput sequencing, and microarrays provide the ability to identify multiple microbes in less than 24 hours with high levels of sensitivity and specificity (see Figure 1). With unique sample prep methods that obviate enrichment, DNA extraction and purification, these technologies will continue to rapidly reduce total test turnaround times into the single digit hours while simultaneously reducing the costs per test within the economics window of the food safety testing world. There are still growing pains as the industry begins to accept these new molecular approaches to microbiology such as advanced training, novel technology and integrated software analysis.
It is easy to envision that the digital data obtained from DNA-based microbial testing could become the next generation gold standard as a “system parameter” to the food supply chain. Imagine for instance that at time of shipping of a container, a data vector would be produced (i.e., time stamp out, location out, invoice, Listeria Speciation and/or Serovar discrimination, Salmonella Speciation and/or Serovar discrimination, refer toFigure 1) where the added microbial data would be treated as another important digital attribute of the load. Though it may seem far-fetched, such early prototyping through the CDC and USDA has already begun at sites in the U.S. trucking industry, based on DNA microarray and sequencing based microbial testing.
Given that “Third Industrial Revolution” technology can now be used to make microbial detection fast, digital, internet enabled and culture free, we argue here that molecular testing of the food chain (DNA or protein based) should, as soon as possible, be developed and validated to replace culture based analysis.
Scallan, E., Hoekstra, R. M., Angulo, F. J., Tauxe, R. V., Widdowson, M. A., Roy, S. L., … Griffin, P. M. (2011). Foodborne illness acquired in the United States–major pathogens. Emerging infectious diseases, 17(1), 7–15. doi:10.3201/eid1701.p11101
Scharff, Robert. (2012). Economic Burden from Health Losses Due to Foodborne Illness in the United States. Journal of food protection. 75. 123-31. 10.4315/0362-028X.JFP-11-058.
Mead, P. S., Slutsker, L., Dietz, V., McCaig, L. F., Bresee, J. S., Shapiro, C., … Tauxe, R. V. (1999). Food-related illness and death in the United States. Emerging infectious diseases, 5(5), 607–625. doi:10.3201/eid0505.990502
Food processing is a multi-trillion dollar industry that encompasses facilities such as bakeries, meat and poultry plants, bottling lines, dairies, canneries and breweries. For all of these food processing plants a commercial flooring system is essential for maintaining a hygienic environment. Few areas of a plant provide as much opportunity for the spread of bacteria, mold, fungi and dust as the floor. Hazardous materials from a contaminated floor can easily be spread from worker’s shoes and mobile equipment. Food processing plants present a unique set of challenges that require careful consideration of floor properties and installation.
Food processing plants floors are subjected to constant, high concentrations of salt, alkaline and oil compounds that substantially degrade the floor and thereby risk food contamination and facility shutdown. These compounds can come from common food production by-products like oils, fats, dairy products, sugar solutions, blood, and natural acids or from harsh cleaners and disinfectants. Even with frequent and thorough cleaning these substances can—and will—result in microbial growth and the spread of bacteria in untreated concrete or poorly installed resinous flooring.
Cleaning floors is an essential part of maintaining food processing operations to keep up with government standards. A proper floor coating is a necessity for dealing with the vigorous, harsh cleaning procedures that typically include very hot water and aggressive cleaning chemicals. Depending on the exposure to corrosive, temperature and moisture conditions a thin film coating may suffice; however, in most cases, a thick, durable floor coating is needed to endure the cleaning operations. If too thin of a coating is used the repeated barrage of high pressure, high-temperature hot water and steam will strip the floor coating. Only an experienced flooring professional can determine the proper floor coating for a facility.
In addition to the properties of the floor coating, proper installation is essential for maintaining a hygienic, safe facility. If a floor is not seamless even the best floor coatings are vulnerable to germ buildup within gaps and cracks. To prevent harmful substance accumulation, a seamless coving transition from the floor to the wall is needed. Not only does that make the floors unsanitary, but it also can spread to other parts of the facility, equipment and product. Coving also aids in the cleaning process by allowing for hosing around the sides and corners of the room where germ buildup is most common.
An often-overlooked—yet critical—aspect of floor installation is having the proper pitch to promote water drainage. Having pools of water is not only dangerous for workers but for product safety. Such an examples of this issue is the Listeria outbreak at cantaloupe producer Jensen Farms, which led to 33 fatalities, 143 hospitalized victims, and ultimately, the end of their business. In the 2011 FDA released a report that focused on “Factors Potentially Contributing to the Contamination of Fresh, Whole Cantaloupe Implicated in the Multi-State Listeria monocytogenes Foodborne Illness Outbreak”. The conclusion was reached that the leading cause of Listeria spreading was due to a poorly constructed packing facility floor that was difficult to clean and allowed water to pool. The best way to prevent a similar situation at your plant is to make sure you get an experienced flooring expert, who understands your facility’s needs, to choose a floor with the right properties and to properly install it.
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