On December 1, 2017, PulseNet, CDC’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.

By 8 October 2018, 12 cases including four deaths had been reported in the affected countries.

In August 2017, Denmark reported the first cluster of cases linked to the consumption of ready-to-eat smoked salmon produced in Poland. Control measures were implemented and other EU Member States and competent authorities were informed.

In October 2017 France reported the detection of the same strain of Listeria in marinated salmon originating from the same Polish processing company as identified in the Danish outbreak investigation.

The most recent case linked to the outbreak was notified in Germany in May 2018.

Due to the lack of whole genome sequencing data from the environmental and food samples taken at the Polish processing plant, it is not possible at present to confirm whether the contamination occurred in the suspected plant. Moreover, until information on the Norwegian primary producers of the salmon used in the contaminated batches has been reported and assessed, the possibility of contamination at primary production level cannot be excluded.

The identification of the same Listeria strain in a salmon product in France and a new human case in Germany suggest that the source of contamination may still be active and that contaminated products have been distributed to other EU countries than Denmark. Pregnant women, the elderly and immunocompromised people are at higher risk of contracting listeriosis.

Johnston County Hams, a Smithfield, N.C. establishment, is recalling approximately 89,096 pounds of ready-to-eat ham products that may be adulterated with Listeria monocytogenes, the U.S. Department of Agriculture’s Food Safety and Inspection Service (FSIS) announced today.

The ready-to-eat deli-loaf ham items were produced from April 3, 2017 to Oct. 2, 2018. The following products are subject to recall:

• Varying weights of 7 to 8-lbs. plastic-wrapped “JOHNSTON COUNTY HAMS, INC. COUNTRY STYLE FULLY COOKED BONELESS DELI HAM.”
• Varying weights of 7 to 8-lbs. plastic-wrapped “Ole Fashioned Sugar Cured The Old Dominion Brand Hams Premium Fully Cooked Country Ham” with Sell-By dates from 4/10/2018 to 9/27/2019.
• Varying weights of 7 to 8-lbs. plastic-wrapped “Padow’s Hams & Deli, Inc. FULLY COOKED COUNTRY HAM BONELESS Glazed with Brown Sugar.”
• Varying weights of 7 to 8-lbs. plastic-wrapped “Premium Fully Cooked Country Ham LESS SALT Distributed By: Valley Country Hams LLC” with Sell-By dates from 4/10/2018 to 9/27/2019.
• Varying weights of 7 to 8-lbs. plastic-wrapped “GOODNIGHT BROTHERS COUNTRY HAM Boneless Fully Cooked.”

The products subject to recall bear establishment number “EST. M2646” inside the USDA mark of inspection. These items were shipped to distributors in Maryland, North Carolina, New York, South Carolina and Virginia.

On September 27, 2018, FSIS was notified that a person ill with listeriosis reported consuming a ham product produced at Johnston County Hams. Working in conjunction with the Centers for Disease Control and Prevention and state public health and agriculture partners, FSIS determined that there is a link between the Listeria monocytogenes illnesses and ham products produced at Johnston County Hams. The epidemiologic investigation identified a total of four listeriosis confirmed illnesses, including one death, between July 8, 2017 and August 11, 2018. FSIS collected two deli ham product samples from the Johnston County Hams, Inc. facility in 2016 and in early 2018. Whole genome sequencing results showed that Listeria monocytogenes identified in deli ham both years was closely related genetically to Listeria monocytogenes from ill people. FSIS is continuing to work with federal and state public health partners to determine if there are additional illnesses linked to these products and will provide updated information should it become available.

Toronto Public Health (TPH) is investigating a case of Listeria infection in a person who consumed food sold at the Druxy’s restaurant located in Princess Margaret Cancer Centre at 610 University Ave. Any individuals who ate non-prepackaged food such as hot and cold deli sandwiches at this restaurant from August 9 to September 26, 2018 are asked to watch for signs and symptoms of Listeria infection and seek medical attention if they have symptoms.

Common symptoms include fever, diarrhea, vomiting, nausea and cramps. Severe symptoms include headache, stiff neck, confusion, loss of balance, and convulsions, and can develop suddenly in those with a weak immune system because of a medical treatment or a medical illness, and the elderly. Symptoms usually occur within three weeks of eating foods contaminated with Listeria. There is no vaccine to prevent the Listeria infection, however it is treated with antibiotics. Healthy people may only experience mild symptoms and usually recover completely. Individuals without symptoms do not need to be tested or treated.

The Listeria infection is a serious but rare illness caused by eating food contaminated with the bacteria Listeria monocytogenes. Common foods contaminated with this bacteria include deli meats and unpasteurized dairy products. People most at risk of developing serious illness are those with weakened immune systems, the elderly and pregnant women.

TPH continues to investigate the matter. As part of this process, TPH staff have completed an extensive risk assessment, collected samples of the surfaces and food for testing, and ordered a thorough cleaning of the restaurant and the restaurant equipment. An alert has been issued to Toronto hospitals, long-term care facilities and doctors’ offices to ensure they are aware of the matter. The restaurant is currently closed and the owner is cooperating with TPH to ensure there is no further risk to the public.

Lipari Foods LLC is voluntarily recalling a brand of pre-made turkey and cheese sandwiches because of the risk of a bacterial contamination that can cause a serious, even fatal, illness.

The company recalled Premo Turkey & Cheese Wedge sandwiches produced on August 8, 2018, and distributed to stores in Illinois, Indiana, Kentucky, Maryland, Michigan, Minnesota, Ohio, Pennsylvania, Tennessee, Wisconsin, and West Virginia, according to a news release.

Testing showed potential listeria contamination. Listeria infections can very serious and sometimes fatal in young children, frail or older people, and people with weakened immune systems.

Symptoms include high fever, severe headache, stiffness, nausea, abdominal pain, and diarrhea. Listeria infection can cause miscarriages and stillbirths.