Thank you, WGS: Listeria linked to smoked salmon in Denmark and France

In Denmark, on 23 August 2017, Statens Serum Institut (SSI) identified a genetic cluster of four human Listeria monocytogenes sequence type (ST) 8 isolates by core genome multilocus sequence typing (cgMLST) [1]. The allele calling was performed in BioNumerics (v7.6.2, Applied Maths, Belgium). We initiated an epidemiological investigation and notified the Danish Central Outbreak Management Group (collaboration between the Danish Veterinary and Food Administration (DVFA), the National Food Institute at the Technical University of Denmark (DTU) and SSI). On 25 August, two additional human isolates were found to belong to the same genetic cluster.

A confirmed case was defined as a person clinically diagnosed with listeriosis after 1 January 2017 with laboratory-confirmed L. monocytogenes ST8 clustering using cgMLST (≤ 5 allelic distance, single linkage). Cases diagnosed before 1 January 2017 with an isolate belonging to this cluster were defined as probable cases.

As of 25 August 2017, the genetic cluster comprised six cases; five confirmed and one probable. The age of the cases ranged from 59 to 96 years (median 80 years) and four were women. All patients had underlying illness and no travel history. One patient died within 30 days of diagnosis. Epidemiological investigations including a standard questionnaire on exposures showed that all five confirmed cases had consumed cold-smoked and/or cured salmon in the 30 days before disease onset. Four cases had bought the salmon in retail chain X. No other food-item was reported as consumed in high frequencies among cases. Epidemiological follow-up for the probable case did not include information on fish consumption.

On 29 August 2017, a comparison between the human outbreak isolates and 16 L. monocytogenes ST8 food- and environmental isolates identified in Denmark from 2014 to August 2017 showed that the human isolates clustered with a food isolate from cold-smoked salmon, cut and packaged at company Y in Poland (zero to two allelic differences using cgMLST). L. monocytogenes had been detected on 31 July 2017 at levels of 110 CFU/g (threshold: 100 CFU/g) at the end of shelf life. The product was widely sold in Denmark and had been sampled by the DVFA in retail chain X, as part of a consumer exposure survey (i.e. analyses project on retail packages). Because the L. monocytogenes concentration had been just above the accepted limit and found at the end of the product shelf life a recall of this batch was not conducted. However, due to the positive finding, follow-up sampling had been performed on the 9 and 10 August 2017 from the central storage unit of retail chain X. L. monocytogenes had been isolated from two batches analysed before end of shelf life. In one sample from the same batches, which was also analysed at the end of the shelf life, on 28 August 2017 a L. monocytogenes level of 240 CFU/g was found. Isolates from the follow-up samples had zero to four allelic differences to the human outbreak isolates using cgMLST.

The human outbreak sequences were also compared to all L. monocytogenes ST8 genomes derived from clinical samples in Denmark from 2012 onwards. Although ST8 genomes from Danish patients in the period 2012–2017 showed high diversity, the outbreak isolates clearly formed a distinct cgMLST cluster with 16 allelic differences to the nearest isolates outside the genetic outbreak cluster and a maximum of nine allelic differences within the cluster (Figure 2a). We investigated the relatedness of outbreak isolates further by single-nucleotide polymorphisms (SNP) analysis performed by both SSI and DTU using two analysis pipelines: Northern Arizona SNP Pipeline (NASP) [2] and CSI Phylogeny version 1.4 from Center for Genomics Epidemiology (CGE), DTU [3] leading to the same conclusion.

On 30 August 2017, DVFA advised retail chain X to recall all cold-smoked salmon produced at company Y. This advice was based on the elevated number of L. monocytogenes (240 CFU/g) found in the product at the end of shelf-life and the link to the outbreak. Retail chain X voluntarily recalled both cold-smoked and cured salmon produced at company Y. As part of the recall procedure, retail chain X informed company Y on the situation. Information from company Y, provided by the Polish food authorities via the European Union Rapid Alert System for Food and Feed (RASFF), showed that the implicated batches were exclusively sold via retail chain X and only in Denmark.

The French National Reference Centre (NRC) for Listeria (Institut Pasteur, Paris), compared the sequences of the Danish human isolates against its database, using cgMLST as previously described [1,4]. A human isolate from a French resident belonged to the same cluster (L2-SL8-ST8-CT771) as the Danish isolates. This French probable case, a female patient in her mid-80s, was diagnosed in June 2016. Epidemiological investigations carried out by Santé Publique France were inconclusive, since food consumption history was not available at the time of diagnosis nor could information on travel to Denmark be retrieved, as the person had since died.

On 6 September 2017, an official control by the Ministry of Economy was carried out at a French retailer where a kosher chilled cured salmon was sampled for analysis. The sample was contaminated with L. monocytogenes at the level of 460 CFU/g and the salmon producer was company Y. An isolate was sent to the French NRC for typing and showed to belong to the same cgMLST type as the Danish outbreak. Further investigations on the food product confirmed that it had not been further processed after production in Poland. The product was recalled and no human cases were linked to its consumption as of beginning of December 2017.

The other nine countries that replied to the EPIS-FWD UI-426 notification (Austria, Finland, Germany, Luxembourg, the Netherlands, Norway, Slovenia, Sweden, United Kingdom) did not report any human or food isolates linked to the Danish outbreak. However, after submission of this report, at the end of November, we were informed through EPIS about three genetically linked human isolates in Germany.

Discussion

Here we report on a listeriosis outbreak and highlight the value of rapidly comparing the genomes of human and food/environmental isolates at the national and international levels.

The fact that the contaminated salmon products identified in Denmark and France were from different batches suggests environmental contamination possibly at the production facility at company Y. It is too early to assess whether any measures taken at company Y have been effective in controlling the outbreak. However, experiences from previous investigations suggest that once L. monocytogenes is detected in one product, the whole production site should be subject to a thorough inspection, and sampling with special attention to all the possible contamination/cross contamination issues before implementing corrective measures [5,6]. Moreover, the risk for L. monocytogenes persistent strains in the production environment requires the close monitoring for several years to ensure the elimination of these [7,8].

Since WGS was introduced for routine surveillance in Denmark, a number of listeriosis outbreaks have been detected and solved, including outbreaks involving cold-smoked ready-to-eat sliced fish products [5]. The present investigation further reinforces the suspicion that ready-to-eat fish products are important sources of L. monocytogenes infections in Denmark, as well as in other countries.

Though only involving a low number of isolates, WGS L. monocytogenes surveillance and communication between countries allowed us to detect and rapidly solve this salmon-associated outbreak, leading to food product recall in two European countries. Compared with previous typing methods, WGS has a higher discriminatory power and the ability to determine genetic distance between isolates. The introduction of WGS for surveillance of food-borne infections has shown that it improves outbreak detection and facilitates outbreak investigations and likely helps reduce the number of infections [4,9-16]. The EPIS-FWD communication platforms allowed for the communication to link cases across borders. However, currently cross-border outbreaks are only detected when case numbers in at least one country exceed normal levels and are notified internationally. Therefore, a possible future system for easy exchange of and comparison of WGS data, e.g. by the use of an agreed cgMLST nomenclature, across borders will enable the identification of more dispersed outbreaks as well as cross-border links between food samples and human infections. This report highlights that by the application of cross-disciplinary and real-time cross-border comparison of WGS data, L. monocytogenes infections can be prevented and thereby providing safer food for at-risk groups such as the elderly, immunodeficient individuals and pregnant women.

Cross-border outbreak of listeriosis caused by cold-smoked salmon, revealed by integrated surveillance and whole genome sequencing (WGS), Denmark and France, 2015 to 2017

Schjørring Susanne, Gillesberg Lassen Sofie , Jensen Tenna, Moura Alexandra, Kjeldgaard Jette S, Müller Luise, Thielke Stine, Leclercq Alexandre, Maury Mylene M, Tourdjman Mathieu, Donguy Marie-Pierre, Lecuit Marc, Ethelberg Steen, Nielsen Eva M. Cross-border outbreak of listeriosis caused by cold-smoked salmon, revealed by integrated surveillance and whole genome sequencing (WGS), Denmark and France, 2015 to 2017. Euro Surveill. 2017;22(50):pii=17-00762. https://doi.org/10.2807/1560-7917.ES.2017.22.50.17-00762

https://eurosurveillance.org/content/10.2807/1560-7917.ES.2017.22.50.17-00762

Denmark: 1 dead, 4 sick from Listeria in salmon

Joe Whitworth of Food Quality News reports that four people have been sickened and one has died from Listeria in salmon processed in Poland and sold in Denmark.

Dansk Supermarked Group issued a recall after Fødevarestyrelsen (Danish Veterinary and Food Administration) detected Listeria monocytogenes in two packs of cold-smoked salmon.

L. monocytogenes was identified at 240 CFU/g in chilled cold smoked salmon.

Listeria positive: Made-to-order salad in Hong Kong

The Centre for Food Safety (CFS) of the Food and Environmental Hygiene Department said on November 15  that a sample of mixed vegetable ingredient of a made-to-order smoked salmon mixed vegetable salad was found to have been contaminated with Listeria monocytogenes. Follow-up is in progress.

smoked-salmon-saladA spokesman for the CFS said, “The CFS took the sample of smoked salmon mixed vegetable salad for testing from a licensed food premises in Sha Tin under a risk assessment study on microbiological quality of vegetables and vegetable salads. The result showed that the salad sample contained Listeria monocytogenes at a level of 2 400 per gram, exceeding the standard of the Microbiological Guidelines for Food which states that no more than 100 of the pathogen per gram should be detected.”
The CFS has informed the premises concerned of the irregularity and instructed it to stop selling the food item in question immediately.

The CFS has also provided health education on food safety and hygiene to the person-in-charge and staff of the premises. The premises have voluntarily suspended its business temporarily to carry out thorough cleaning and disinfection. The CFS is also tracing the sources of the ingredients of the affected food item.

“Listeria monocytogenes can be easily destroyed by cooking but can survive and multiply at refrigerator temperatures.

Listeria forces recall of NZ smoked salmon products

On 27 July 2016, Prime Foods NZ Ltd recalled 50g packs of its smoked salmon slices. The recall was extended on 29 July 2016 to also include:

Prime Smoke brand Smoked Salmon Shavings (100g)

Prime Smoke brand Smoked Salmon Mixed Pieces (500g)

prime-smoke-smoked-salmon-1-600Product identification

Product type                       Smoked Salmon (Ready-to-eat meat product)

Name of product               Prime Smoke brand Smoked Salmon Slices (50g)
Prime Smoke brand Smoked Salmon Shavings (100g)
Prime Smoke brand Smoked Salmon Mixed Pieces (500g)

Batch and date marking      Prime Smoke brand Smoked Salmon Slices (50g)
Batch code 18321507
Use by 25/08/2016

Prime Smoke brand Smoked Salmon Shavings (100g)
Batch Code 17621207
Use By 22/08/2016

Prime Smoke brand Smoked Salmon Mixed Pieces (500g)
Batch Code 17621207
Use By 22/08/2016

Package size and description         Sold in plastic vacuum packages of 50g, 100g and 500g.

Distribution                         The products are sold in retail outlets and supermarkets throughout New Zealand.

Fjord Laks brand Scottish smoked salmon recalled due to Clostridium potential

The food recall warning issued on July 02, 2016 has been updated to include additional product information. This additional information was identified during clostridium.salmon.jul.16the Canadian Food Inspection Agency’s (CFIA) food safety investigation.

A & E Distribution Inc. is recalling Fjord Laks brand Scottish Smoked Salmon from the marketplace because it may permit the growth of Clostridium botulinum if sold refrigerated. Consumers should not consume the recalled product described below.

If you think you became sick from consuming a recalled product, call your doctor.

Check to see if you have recalled product in your home. Recalled product should be thrown out or returned to the store where it was purchased.

Food contaminated with Clostridium botulinum toxin may not look or smell spoiled but can still make you sick. Symptoms can include nausea, vomiting, fatigue, dizziness, blurred or double vision, dry mouth, respiratory failure and paralysis. In severe cases of illness, people may die.

This recall was triggered by the CFIA inspection activities. The CFIA is conducting a food safety investigation, which may lead to the recall of other products. If other high-risk products are recalled, the CFIA will notify the public through updated Food Recall Warnings.

The CFIA is verifying that industry is removing recalled product from the marketplace.

There have been no reported illnesses associated with the consumption of this product.

Smoked salmon recalled for Listeria

Loki Fish Company of Seattle, WA is voluntarily recalling two lots of Wild Smoked Pink Salmon Portions, due to a positive test result for Listeria monocytogenes.

loki.list.salmonThe affected Wild Smoked Pink Salmon Portions comes in a 4-7 ounce, clear plastic package. The lot 121215 5594 or 121215 5613 is found on the back of the package.

Product was distributed to retail stores in Oregon and Washington, via mail order, and sold at Seattle area farmers markets. For a list of retail outlets and farmers markets that may have carried the identified product, and for other updates, please go to www.lokifish.comdisclaimer icon.

No illnesses have been reported to date in connection with Loki Fish Company product. The product is processed by Felix Custom Smoking, a Loki Fish Company co-packing vendor.

The retail sample was collected during routine sampling activities conducted by Washington State Department of Agriculture (WSDA) and presence of Listeria monocytogenes was confirmed. This recall is being made with the knowledge of the U.S. Food and Drug Administration and WSDA.

Consumers who have purchased the identified product are urged not to consume and return it to the place of purchase for a full refund. In addition to the Loki Fish Company website, consumers may contact the company directly with questions at 206-937-1048 between Monday-Friday, 9am-4pm PST.

“As a family owned fishing business that direct markets our catch, nothing is more important to us than the safety of the products we sell,” said Loki Fish Company General Manager, Dylan Knutson. Knutson continued, “We have ordered additional tests to make sure we isolate the contamination and fully understand its cause. As soon as we have additional information, we will share it with the public as well as with the FDA and WSDA.”

Not the best idea: serving smoked salmon to hospital patients

I’m not a huge smoked salmon fan, but when there’s not much to choose on a breakfast buffet, I’ll grab some with a bagel and cream cheese.

With its history of Listeria monocytogenes risks, I wouldn’t serve smoked salmon to someone who was immunocompromised.shutterstock_187930064

Or a hospital patient.

According to EJ Insight, a 79-year-old hospital patient in Hong Kong has listeriosis following a smoked salmon sandwich.

The Centre for Health Protection (CHP) epidemiological investigations revealed that the patient had consumed high-risk foods including sandwiches with smoked salmon provided by the kitchen of the private hospital in late December, Ming Pao Daily reported.

The patient has been confined at the hospital since Sept. 12 last year for several chronic diseases. She developed fever and her body conditions deteriorated since Jan. 1.

While a sample of smoked salmon collected from the hospital kitchen tested negative for Listeria monocytogenes, the patient’s blood culture yielded the bacteria.

The Centre for Food Safety (CFS) of the Food and Environmental Hygiene Department subsequently collected five smoked salmon samples and 19 environmental samples from the factory of Elegant Fine Food Limited, the food supplier, on Shipyard Lane in Quarry Bay.

Four of the samples tested positive for Listeria monocytogene, while all environmental samples were negative.

The CFS has ordered the food supplier to immediately recall all of its smoked salmon products while all of its existing stocks were confiscated. Its production lines have been suspended for sterilization.

A CFS spokesperson said investigations are ongoing.

Why is this on a hospital menu?

Netherlands: Salmonella outbreak from salmon cost €1.7m

For 20 years now, smoked salmon on bagels has been my quick breakfast go-to while driving to the rink in the early morning.

rivm-cost-salmonella_largeUnfortunately, the bagels in Australia suck.

An outbreak of Salmonella Thomson due to smoked salmon cost €1.7m, according to RIVM, the Dutch National Institute for Public Health and the Environment.

 

Marijuana-infused salmon in Denver deli? Inspector calls foul

On April 20, Rosenberg’s Bagels and Delicatessen in Denver made a marijuana-infused salmon for a private 4/20 party. Once the Denver Department of Environmental Health saw the video, a food inspector visited the restaurant at 27th Avenue and Welton Street in Five Points.

smoke.salmon.marijuana“A regulated food establishment is not allowed to prepare marijuana foods in their kitchen,” said Danica Lee, food safety section manager for the Denver Department of Health. “We did issue a cease-and-desist order to make the facility understand that they cannot do that any longer.”

The YouTube video shows where science meets cooking, as a salmon is infused with marijuana, then put in the kitchen’s smoker.

“We certainly did check to make sure that they had cleaned the equipment properly and taken care of the issue, and that they’re aware of what they can and can’t do moving forward,” said Lee. “It is important that even when a facility is closed and not operating that they’re not doing anything in that kitchen that’s in violation of the food code.”

“We took our deep clean, which uses both bleach and heavy duty oven cleaner, and scrubbed every aspect of the oven, as well as did a high-temperature burn,” said Rosenberg’s owner Joshua Pollack.

Pollack spoke with 7NEWS shortly after a food inspector came by to make sure there was no more pot baking going on.

“The store was completely shut down because we’re closed on Mondays. None of it was sold. I was all for private consumption. Everyone was 21 years or older,” said Pollack. “Nothing here is infused. We don’t sell any infused products.”

4 dead, 23000 sickened in 2012 from Salmonella Thompson related to smoked salmon in the Netherlands

On 15 August 2012, an increase in the number of Salmonella Thompson cases was noticed by the Salmonella surveillance in the Netherlands. A case–control study was performed, followed by a food investigation. In total 1,149 cases were laboratory-confirmed between August and December 2012 of which four elderly (76–91 years) were reported to have died due to the infection. The cause of the outbreak was smoked salmon processed at a single site.

r-SMOKED-SALMON-SALMONELLA-large570The smoked salmon had been continuously contaminated in the processing lines through reusable dishes, which turned out to be porous and had become loaded with bacteria.

This is the largest outbreak of salmonellosis ever recorded in the Netherlands. The temporary closure of the processing site and recall of the smoked salmon stopped the outbreak. An estimated four to six million Dutch residents were possibly exposed to the contaminated smoked salmon and an estimated 23,000 persons would have had acute gastroenteritis with S. Thompson during this outbreak.

This outbreak showed that close collaboration between diagnostic laboratories, regional public health services, the national institute for public health and the food safety authorities is essential in outbreak investigations.

Eurosurveillance, Volume 19, Issue 39

Friesema I, de Jong A, Hofhuis A, Heck M, van den Kerkhof H, de Jonge R, Hameryck D, Nagel K, van Vilsteren G, van Beek P, Notermans D, and van Pelt W.