Nineteen sick people are aged 63 to 93, including 13 men and six women. Patients have been reported from 10 different regions.

Six people with listeriosis have died. However, it is unclear what role the infection played in their death because most patients had other severe underlying diseases.

People have been sick with the same type of Listeria since autumn 2022, but 15 cases occurred from the end of May this year, said Folkhälsomyndigheten (the Public Health Agency of Sweden).

Of cases with available information, 14 reported eating vacuum-packed salmon from one of two brands before falling sick. Both these brands are produced by Leröy Seafood, and Listeria was detected in products and environmental samples in the firm’s facility.

In most cases, samples have only been analyzed qualitatively so it is unclear if Listeria was above the limit of 100 CFU/g, according to Livsmedelsverket (the Swedish Food Agency).

“For Leröy Smögen Seafood, safe and secure food is our priority, and we take this incident very seriously. We are doing everything we can to ensure this does not happen again. We have a good cooperation and dialogue with the Swedish Food Agency,” said a company statement.

Finding the source of infections
Further analysis of samples from food, the environment, and human cases found the same type of Listeria, which points to the salmon products being the likely source of infection. The company has increased sampling and is carrying out further clean-up measures at the facility.

In early August, the retailer Axfood recalled a batch of Falkenberg Seafood cold smoked salmon 200-grams after low levels of Listeria were found.

The product was available for sale in the majority of Axfood’s stores. Listeria was detected during the retailer’s internal checks.

“The production has not been stopped, but all batches are currently analyzed for the presence of Listeria before release on the market. The company must take action following its HACCP-based procedures. They must also investigate the cause of contaminated products with Listeria monocytogenes and take measures to prevent such contamination. This may involve changes to HACCP-based procedures or other measures,” said Mats Lindblad from Livsmedelsverket.

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Folkhälsomyndigheten (the Public Health Agency of Sweden) said deaths of three of the older patients were connected to their Listeria infections but it is not clear if they died with or because of listeriosis.

From the end of May to the beginning of July, 10 people contracted Listeria infections caused by the same type of the bacteria. Another four people fell ill in late 2022 from this strain.

Patients are 10 men and four women aged 63 to 93 years old. They live in eight different regions in the country.

Based on information from a questionnaire given to patients about foods they ate before becoming sick, many reported eating gravad or cold-smoked salmon but the exact product that caused the outbreak is not yet clear.

Warning for vulnerable groups
Folkhälsomyndigheten, Livsmedelsverket (the Swedish Food Agency) and regional infection control units are investigating the illnesses.

Livsmedelsverket said Listeria can cause serious illness for people in at-risk groups, such as pregnant women, the elderly and people with impaired immune systems.

“Those who belong to a risk group — or who are to offer food to someone in a risk group — can reduce the risk of infection by following the Swedish Food Agency’s advice on Listeria. Certain foods such as blue cheeses should be avoided completely, while other foods such as cold smoked and gravad salmon should be eaten within a week of the date on the packaging,” said Jonas Toljander, a microbiologist at Livsmedelsverket.

In 2022, 125 listeriosis cases were reported compared to 107 the year before. The median age was 79 and as in previous years, most were older than 80. Overall, 45 people died within one month of diagnosis.

National and local authorities took 266 samples from different types of food to test for the presence or absence of Listeria monocytogenes in 2022. The pathogen was detected eight times. Two of these were vacuum-packed salmon taken as part of work into a suspected food poisoning or complaint.

About Listeria infections
Food contaminated with Listeria monocytogenes may not look or smell spoiled but can still cause serious and sometimes life-threatening infections. Anyone who has developed symptoms of Listeria infection should seek medical treatment and tell their doctors about the possible Listeria exposure.

Also, people should monitor themselves for food poisoning symptoms during the coming weeks because it can take up to 70 days after exposure to Listeria for symptoms of listeriosis to develop. 

Symptoms of Listeria infection can include vomiting, nausea, persistent fever, muscle aches, severe headache, and neck stiffness. Specific laboratory tests are required to diagnose Listeria infections, which can mimic other illnesses. 

Pregnant women, the elderly, young children, and people such as cancer patients who have weakened immune systems are particularly at risk of serious illnesses, life-threatening infections, and other complications. Although infected pregnant women may experience only mild, flu-like symptoms, their infections can lead to premature delivery, infection of the newborn, or even stillbirth.

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A report by the National Veterinary Institute (SVA), Folkhälsomyndigheten (the Public Health Agency of Sweden), Livsmedelsverket (the Swedish Food Agency) and Jordbruksverket (Swedish Board of Agriculture) showed a rise for Campylobacter, Salmonella, Listeria, and E. coli infections. Some of this was because of increased travel and more people being infected abroad.

A total of 5,165 cases of campylobacteriosis were reported in 2022 and 57 percent of these were domestic. This is up on more than 4,000 cases in 2021. For domestic infections in 2022, the median age was 51 with a range of 0 to 101. More men, 54 percent, than women were sick.

A correlation between human cases and Campylobacter-positive broiler batches underscores the need for further preventive measures, said the report.

Salmonella stats
In total, 1,137 cases of salmonellosis were reported, compared to 944 in 2021. Almost 450 people were considered to have been infected abroad. Among domestic cases, the median age was 44 and incidence was highest for children younger than 5 years old. Of serotyped isolates from domestic patients, the most common were Salmonella Typhimurium, Enteritidis, Agona and monophasic Salmonella Typhimurium. Another 59 different types were identified during 2022.

Six outbreaks involving 10 or more people occurred. In December, Salmonella Enteritidis was detected in laying hens at the largest egg producing facility in Sweden. Although it is the most common cause of salmonellosis in Europe, in Sweden the serovar had been detected in commercial laying hens only three times since 2003. The outbreak has caused 81 human infections, mainly during 2023.

The source in the laying flock has yet to be identified. However, isolates are genetically similar to those from other EU outbreaks caused by eggs contaminated with Salmonella Enteritidis. Belgium had a large outbreak with an almost identical strain in early 2022 linked to eggs from a domestic producer. The outbreak strain is also similar to a smaller Danish egg-linked event in summer 2022.

Fifteen people were infected with Salmonella Liverpool in frozen pre-cooked crayfish from China. Five cases were also recorded in 2021. However, the producer had only been approved for export in February 2022 and the importer had received crayfish from another firm in past years, so it was not possible to identify a connection to previous ill people.

Two Swedish producers were connected to a Salmonella typhimurium outbreak caused by rocket salad. Overall, 109 people fell sick and patients were also recorded in Finland. A Salmonella Agona outbreak affected 35 people. Cases were also recorded in Norway and the Netherlands. The suspected source was Spanish cucumbers.

E. coli and Listeria
In 2022, 857 E. coli cases were reported of which 583 were domestically acquired. As in previous years, the incidence was highest in children younger than 5. In total, 79 different serotypes were identified. The most common types were O157:H7, O26:H11, and O103:H2. A total of 653 patients were reported in 2021.

STEC-associated Hemolytic Uremic Syndrome (HUS) was reported in 19 patients of which 17 were domestically acquired. Eleven HUS patients were children under the age of 10. No single serotype caused more than two HUS cases.

Three investigations were carried out after human cases were detected with suspected connection to farm animals. Suspicions fell on drinking unpasteurized milk or direct contact with cattle. All farms were negative for STEC. A source could not be found in three outbreaks caused by O121:H19, O63:H6 and a combination of O103:H2 and O157:H7.

In total, 125 Listeriosis cases were reported compared to 107 in 2021. The median age was 79 and as in previous years, most were older than 80. Sixty-seven cases were females and 57 were males. Overall, 45 people died within one month from diagnosis.

Five patients with a rare strain of Listeria monocytogenes in Sweden were included in a larger cluster with cases from 2019 to 2022. All were notified in autumn but the source of infection was not identified.

Salmon raw material that became contaminated during processing in Norway was the source of one outbreak with four patients. Sixteen cases recorded from 2020 to 2022 were linked to products from a meat processing plant.

Listeria monocytogenes was detected in an opened pack of a washed rind cheese taken at the home of a sick person. Four other patients from 2018 through 2022 were identified. However, analysis at EU level found the source was salmon and not cheese. The five patients in Sweden were linked to 11 cases in five other countries from 2017 to 2022.

Cryptosporidium, Yersinia and Brucella
In 2022, 716 cryptosporidiosis cases were reported. The median age was 38 and 55 percent were women. A total of 550 people were infected in Sweden. The total is up from 524 cases in 2021.

Between late September and mid-October, 107 cases with Cryptosporidium parvum were detected in 15 different regions. The median age was 40 and more females than males were infected. Epidemiological investigations pointed toward contaminated frisée lettuce in ready-to-eat green leaf mixes as the probable cause.

A total of 238 Yersinia cases were reported, down from 313 in 2021. Like previous years, the incidence was highest among children younger than 5. Yersinia is not part of the national microbial surveillance program in Sweden but no outbreaks were detected.

In 2022, 10 cases of brucellosis were reported. They ranged in age from 25 to 71 including five men and five women. Three people were infected in Sweden by a goat cheese from Iraq. Six acquired their infections in Iraq and for one person the country of infection was unknown. For seven cases, unpasteurized dairy products were the probable source of infection.

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European regulation lists 14 allergens that are subject to labeling and information requirements.

Inspections by the Netherlands Food and Consumer Product Safety Authority (NVWA) showed that 60 percent of nearly 13,000 companies in retail, hospitality, and catering did not properly inform customers about which allergens are used in food. Information can be provided orally or in writing.

Results from checks in 2022 found that 6 in 10 firms did not inform customers completely or correctly about allergens in unpackaged foods. Sometimes labels were not kept or details of ingredients were not recorded.

Despite more inspections, there was hardly any improvement from 2021, said NVWA. The agency added it would continue monitoring the situation and try to help the sector improve.

Companies in the hospitality industry such as restaurants, hotels, and cafeterias, performed slightly better than in 2021 but the situation was worse in the retail sector. Enforcement action, in the form of written warnings or fines, was taken at sites that did not meet the requirements.

Written allergen information is often incomplete and sometimes incorrect. It is also not always visible to consumers, said NVWA. Employees can usually say which allergen is in a product, but the information is not available elsewhere in writing or electronically, so the inspector cannot check if it is correct.

Danish findings
In Denmark, the Danish Veterinary and Food Administration (Fødevarestyrelsen) verified companies’ labeling of pre-packed food, including for allergens.

Requirements state that allergens must be highlighted in a way that distinguishes them from other ingredients on the list, for example by the font, style, or background color.

Random checks at 773 companies from June to December 2022 found serious errors in the labeling of allergens at 1.4 percent of businesses, who were fined.

The campaign shows that controls should continue to focus on the labeling of pre-packaged foods, especially with allergenic ingredients, as it is a big challenge for companies and could have severe consequences for allergic consumers, said authorities.

“Results show that companies generally have a good grasp of the rules, but we expect companies to do better – not least because the rules on allergen labeling are so important for allergy sufferers,” said Henrik Dammand Nielsen, of the Danish Veterinary and Food Administration.

Swedish results
In a national control project in Sweden in 2022, the allergen information provided for 4,344 products at 2,172 restaurants, cafes, and other large outlets was reviewed. Incorrect information was provided for 17 percent of products and 25 percent of the businesses.

Mustard and celery were the allergens that caused businesses the most trouble. Incorrect information regarding milk, eggs, and gluten was given in more than 100 cases each. The problem was not as bad for peanuts and nuts.

The project showed that how the information is available – written or provided verbally – had no bearing on how likely it was to be correct.

“The fact that an allergy sufferer so often risks getting wrong information in restaurants is very serious as it can lead to allergic reactions. Restaurants and similar businesses have an obligation to inform about allergenic ingredients in the food they serve,” said Maria Svensson, unit manager for food inspection in the city of Malmö.

Anyone who has received incorrect information about allergens at a restaurant or other outlet should report it to their local municipality, said the Swedish Food Agency (Livsmedelsverket).

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The Public Health Agency of Sweden (Folkhälsomyndigheten) said new findings of Salmonella at the site of the same company were made in mid-February. This prompted another wave of recalls in February and March.

In late December 2022, Salmonella Enteritidis was identified at CA Cedergren, a major producer, in one of the egg-laying stables during a routine environmental sampling check. Eggs were then recalled by Coop, Axfood, ICA, Lidl, and Kronägg. 

Investigations found Salmonella from the production environment in December was identical to isolates from sick people.

No cases linked to second recall
In an update this past week, Folkhälsomyndigheten said 79 people were sick in the outbreak, which is up three cases since mid-February.

The latest date of illness onset among reported cases is early February. So far, nothing indicates that anyone has been infected in connection with the detection of Salmonella made in February during enhanced sampling, said health officials.

Patients from 16 different regions are sick with the outbreak strain of Salmonella Enteritidis.

Cases include 36 women and 43 men. They fell ill between Dec. 6, 2022, and Feb. 4, 2023, and are between 1 to 91 years old with a median age of 35.

After Salmonella was found at the farm in Småland in December, local media reported that the Swedish Agency for Agriculture said that 165,000 laying hens must be killed. The latest finding means 160,000 hens will be killed.

National control program data shows it is unusual to find Salmonella in Swedish meat or eggs and most people who get sick are usually affected abroad or by imported food.

The outbreak is being investigated by the Swedish Agency for Agriculture, the Swedish Food Agency (Livsmedelsverket), the Public Health Agency of Sweden as well as regional and local authorities.

About Salmonella infections
Food contaminated with Salmonella bacteria does not usually look, smell, or taste spoiled. Anyone can become sick with a Salmonella infection. Infants, children, seniors, and people with weakened immune systems are at higher risk of serious illness because their immune systems are fragile.

Anyone who has eaten or handled any of the implicated eggs and developed symptoms of Salmonella infection should seek medical attention. Sick people should tell their doctors about the possible exposure to Salmonella bacteria because special tests are necessary to diagnose salmonellosis. Salmonella infection symptoms can mimic other illnesses, frequently leading to misdiagnosis.

Symptoms of Salmonella infection can include diarrhea, abdominal cramps, and fever within 12 to 72 hours after eating contaminated food. Otherwise, healthy adults are usually sick for four to seven days. In some cases, however, diarrhea may be so severe that patients require hospitalization.

Older adults, children, pregnant women, and people with weakened immune systems, such as cancer patients, are more likely to develop a severe illness and serious, sometimes life-threatening conditions.

Some people get infected without getting sick or showing any symptoms. However, they may still spread the infections to others.

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The Public Health Agency of Sweden (Folkhälsomyndigheten) said 76 people were sick, which is up from 48 in a previous update.

Patients from 16 different regions have been confirmed as infected with the outbreak strain of Salmonella Enteritidis.

Sick people include 36 women and 40 men who fell ill between early December 2022 and the end of January 2023. They are one to 91 years old with a median age of 35.

In late December 2022, Salmonella Enteritidis was identified at CA Cedergren, a major Swedish producer in one of the egg-laying stables during a routine environmental sampling check.

After Salmonella was found at the farm in Småland, the Swedish Agency for Agriculture said that 165,000 laying hens must be killed. Similar strains have previously been found in several other countries.

National control program data shows it is unusual to find Salmonella in Swedish meat or eggs and most people who get sick are affected abroad or by imported food.

The outbreak has been linked to eggs, which were recalled by Coop, Axfood, ICA, Lidl, and Kronägg and are now past their shelf life dates.

Recent cases appear to involve people who have carried the infection for a while before being tested and getting sampling results or instances of secondary infections from other patients.

The outbreak was investigated by the Swedish Agency for Agriculture, the Swedish Food Agency (Livsmedelsverket), the Public Health Agency of Sweden as well as regional and local authorities.

About Salmonella infections
Food contaminated with Salmonella bacteria does not usually look, smell, or taste spoiled. Anyone can become sick with a Salmonella infection. Infants, children, seniors, and people with weakened immune systems are at higher risk of serious illness because their immune systems are fragile.

Anyone who has eaten any of the implicated eggs and developed symptoms of Salmonella infection should seek medical attention. Sick people should tell their doctors about the possible exposure to Salmonella bacteria because special tests are necessary to diagnose salmonellosis. Salmonella infection symptoms can mimic other illnesses, frequently leading to misdiagnosis.

Symptoms of Salmonella infection can include diarrhea, abdominal cramps, and fever within 12 to 72 hours after eating contaminated food. Otherwise, healthy adults are usually sick for four to seven days. In some cases, however, diarrhea may be so severe that patients require hospitalization.

Older adults, children, pregnant women, and people with weakened immune systems, such as cancer patients, are more likely to develop severe illnesses and serious, sometimes life-threatening conditions. Some people get infected without getting sick or showing any symptoms. However, they may still spread the infections to others.

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The Public Health Agency of Sweden (Folkhälsomyndigheten) also warned this figure is expected to increase again.

There are 48 people from 13 regions confirmed to have been infected with the outbreak strain of Salmonella Enteritidis, this is up from 22 people in 11 regions.

Illnesses occurred between early December and mid-January. Of those sick, 22 are women and 26 are men. The age range is 1 to 90 years old with a median age of 34.

The outbreak has been linked to eggs, which have been recalled. Analysis has revealed Salmonella found during environment sampling at an egg producer is identical to isolates from sick people.

Typing of Salmonella isolates from people that reported having food containing eggs from recalled batches is ongoing, which is why the Public Health Agency of Sweden believes the number of people affected will go up.

Recall and public warning
No contaminated eggs from recalled lots should be left in shops or restaurants but it is possible people still have them in their homes.

Alerts have been made by Coop, Axfood, ICA, Lidl, and Kronägg involving different pack sizes of eggs. Some have a best-before date up to Jan. 28, 2023.

These firms said they were taking the incident seriously and were investigating, with the supplier, how contamination could have occurred. This included trying to make sure that something similar does not happen again.

In late December 2022, Salmonella Enteritidis was identified at CA Cedergren, a major Swedish producer in one of the egg-laying stables during a routine check.

After Salmonella was found at the farm in Småland, the Swedish Agency for Agriculture said that 165,000 laying hens must be killed.

The outbreak is being investigated by the Swedish Agency for Agriculture, the Swedish Food Agency (Livsmedelsverket), the Public Health Agency of Sweden as well as regional and local authorities.

National control program data shows it is very unusual to find Salmonella in Swedish meat or eggs and most people who get sick are affected abroad or by imported food.

Swedish Salmonella control covers feed, animals, and food which means that positive findings are handled along the entire food chain. Authorities and industry try to prevent and combat Salmonella through statutory and voluntary control programs. There is mandatory monitoring of all commercial poultry flocks, where regular sampling takes place on the farm.

In the event of an outbreak where the Swedish Board of Agriculture is involved and decides on various measures, restrictions, and requirements, animal owners may be entitled to compensation.

About Salmonella infections
Food contaminated with Salmonella bacteria does not usually look, smell, or taste spoiled. Anyone can become sick with a Salmonella infection. Infants, children, seniors, and people with weakened immune systems are at higher risk of serious illness because their immune systems are fragile.

Anyone who has eaten any of the implicated eggs and developed symptoms of Salmonella infection should seek medical attention. Sick people should tell their doctors about the possible exposure to Salmonella bacteria because special tests are necessary to diagnose salmonellosis. Salmonella infection symptoms can mimic other illnesses, frequently leading to misdiagnosis.

Symptoms of Salmonella infection can include diarrhea, abdominal cramps, and fever within 12 to 72 hours after eating contaminated food. Otherwise, healthy adults are usually sick for four to seven days. In some cases, however, diarrhea may be so severe that patients require hospitalization.

Older adults, children, pregnant women, and people with weakened immune systems, such as cancer patients, are more likely to develop severe illnesses and serious, sometimes life-threatening conditions.

Some people get infected without getting sick or showing any symptoms. However, they may still spread the infections to others.

(To sign up for a free subscription to Food Safety News, click here.)

The Salmonella Enteritidis outbreak involves 22 people from 11 different regions. Patients are aged between 7 and 90 years old. A dozen of the patients are women and illnesses occurred between early December and the start of January.

In late December 2022, Salmonella Enteritidis was identified at CA Cedergren, a major Swedish producer in one of the egg-laying stables during a routine check, which led to several recalls.

Some sick people ate meals containing eggs from the now-recalled batches, so there is a likely connection to the Salmonella finding at the egg producer, said the Public Health Agency of Sweden (Folkhälsomyndigheten).

In recent days, a larger number of Salmonella infections have been reported than was expected. These isolates have not yet been typed to determine the strain. However, several ill people mentioned the consumption of products with eggs from suspected contaminated batches so there is a good chance the number of people in the outbreak will increase.

Dent to Sweden’s good Salmonella record
Because of the recalls, there should be no contaminated eggs left in stores or restaurants but it is possible that consumers still have them at home.

The outbreak is being investigated by the Swedish Agency for Agriculture, the Swedish Food Agency (Livsmedelsverket), the Public Health Agency of Sweden as well as regional and local authorities.

When the prevalence of Salmonella in certain animals or food is very low and strict national control programs apply, the European Commission may grant special guarantees to an EU country. This includes extended monitoring showing the absence of Salmonella before sending shipments to those countries. Such guarantees are in place for Sweden, Finland, Denmark, and Norway.

National control program data shows it is very unusual to find Salmonella in Swedish meat or eggs and most people who get sick are affected abroad or by imported food. However, since the detection of Salmonella in Swedish eggs in December a number of recalls have been issued.

Alerts have been made by Coop, Axfood, ICA, Lidl, and Kronägg involving different pack sizes of eggs. Some have a best-before date up to Jan. 28, 2023.

These firms said they are taking the incident seriously, and were investigating, with the supplier, how contamination could have occurred. This included trying to make sure that something similar does not happen again.

Salmonella was found at the farm in Småland in late December and the Swedish Agency for Agriculture has decided that 165,000 laying hens must be killed.

About Salmonella
Food contaminated with Salmonella bacteria does not usually look, smell, or taste spoiled. Anyone can become sick with a Salmonella infection. Infants, children, seniors, and people with weakened immune systems are at higher risk of serious illness because their immune systems are fragile, according to the CDC.

Anyone who has eaten any recalled products and developed symptoms of Salmonella food poisoning should seek medical attention. Sick people should tell their doctors about the possible exposure to Salmonella bacteria because special tests are necessary to diagnose salmonellosis. Salmonella infection symptoms can mimic other illnesses, frequently leading to misdiagnosis.

Symptoms of Salmonella infection can include diarrhea, abdominal cramps, and fever within 12 to 72 hours after eating contaminated food. Otherwise, healthy adults are usually sick for four to seven days. In some cases, however, diarrhea may be so severe that patients require hospitalization.

Older adults, children, pregnant women, and people with weakened immune systems, such as cancer patients, are more likely to develop severe illnesses and serious, sometimes life-threatening conditions. Some people get infected without getting sick or showing any symptoms. However, they may still spread the infections to others.

(To sign up for a free subscription to Food Safety News, click here.)

The Norwegian Institute of Public Health (FHI) said 58 people are sick in the Salmonella Agona outbreak and 23 had been hospitalized. This is up from 31 sick and 13 hospitalizations.

In Sweden, 26 people have been affected, according to the Public Health Agency of Sweden (Folkhälsomyndigheten).

Norwegian situation

In Norway, people in 10 regions were diagnosed with infections from Nov. 7 to 29 with a peak in the middle of the month. Salmonella Agona is a rare type of Salmonella in Norway and Europe.

Those sick are aged 1 to 88 years old and 27 of them are women. Bacteria with the same genetic profile, meaning they were likely infected by the same source, have been detected in 37 of 58 patients. For the other 21, sequencing results from laboratory tests are pending.

The majority of sick people live in Viken, followed by Vestland and Vestfold og Telemark. Single-figure patient numbers have been recorded in Innlandet, Trøndelag, Troms og Finnmark, Møre og Romsdal, Oslo, Rogaland, and Nordland.

Source of the outbreak not yet known
An investigation to find the source is ongoing with FHI, local officials, the Norwegian Food Safety Authority (Mattilsynet), and the Veterinary Institute. The cause is believed to be an imported food product distributed across the country and also in Sweden.

Heidi Lange, from FHI, said patients are being interviewed to see if there is a common source of infection.

“In addition, we also collect information from purchase receipts in cooperation with the Norwegian Food Safety Authority and the grocery industry. We do this because it can be challenging to remember everything that was eaten before illness,” she said.

“FHI plans to carry out a case-control study. This involves comparing what patients have eaten with what a random selection of other people have eaten within the same time period. In this way, we can test out various clues about the source of the outbreak, and whether there is an increased risk of disease linked to certain foods.”

In Sweden, 26 people have fallen ill since the start of November. Patients range in age from 3 to 86 years old and are from 12 different regions in the country. Fifteen cases are women.

Whole genome sequencing has shown they have the same type of Salmonella Agona, so are suspected of having been infected by a common source.

Folkhälsomyndigheten, local infection control units, and the Swedish Food Agency (Livsmedelsverket) are helping Norwegian authorities to search for the source of the outbreak.

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The number of outbreaks reported to the Swedish Food Agency (Livsmedelsverket) in 2020 and 2021 was affected by measures taken during the pandemic.

There were 251 reports of suspected or confirmed food poisoning outbreaks with 1,467 illnesses. Both the number of reports and the number of cases increased compared to 160 outbreaks and 1,314 cases in 2020 but are still lower than the historical average.

When several Coronavirus-related restrictions were lifted in the autumn of 2021, the number of cases increased. Sixteen major outbreaks occurred during this season.

Eleven people have been hospitalized in seven outbreaks and one person died during a Campylobacter epidemic which infected eight people.

Outbreak causes

For 213 reports and 843 cases, the cause was unknown. Bacteria were blamed for 26 outbreaks and 343 cases, followed by viruses in 12 events with 194 cases, and other agents such as histamine or lectins in seven reports with 52 cases.

Norovirus caused the most with 11 outbreaks and 189 cases, followed by Salmonella with eight outbreaks and 179 cases. Norovirus declined in 2021 but Salmonella rose.

Listeria was behind five outbreaks with 14 infections and Campylobacter caused five with 23 cases. Four outbreaks with 78 infections were due to Shiga toxin-producing E. coli (STEC). Cryptosporidium affected 23 people and one Yersinia enterocolitica outbreak sickened 16.

Four other outbreaks that also had cases in previous years were reported. In a Listeria monocytogenes outbreak, 17 people have been affected since 2019 with the source unknown. Tahini and halva have sickened 41 people since 2019.

Food categories with the most reported illnesses were vegetables with 210 cases and seafood such as oysters, mussels, and fish products with 151 patients.

Three histamine outbreaks were linked to tuna from Southeast Asia and frozen raspberries from Bosnia were behind one incident. A Salmonella outbreak was traced to alfalfa sprouts where seeds came from Italy and an outbreak caused by Yersinia enterocolitica was linked to iceberg lettuce from Spain. The Cryptosporidium outbreak was due to kale produced in Sweden.

In 55 percent of reports, and for 41 percent of the cases, the source of infection was food contaminated in facilities such as restaurants, cafes, or cooking kitchens in schools.

The top contributing factor was “infection/poor hygiene among staff”, which was started in 18 of 52 reports. This means people who handled food were carriers of infection or did not follow hygiene practices. The second most common factor was “wrong storage with respect to time and temperature”, which was listed in 15 reports.

Inspection results

Another report has found food controls are largely back to normal after a decline due to the peak of the COVID-19 pandemic.

Controls of food and food businesses involve several different authorities including the Swedish Food Agency, County Administrative Boards, and municipal control authorities.

The number of inspections in manufacturing, distribution, and sales have increased after the sharp drop during the pandemic in 2020. A larger percentage of high-risk facilities have also been inspected.

However, there are areas for improvement. For example, in primary production, local authorities did not reach the goal of 1,000 checks. In 2021, only 72 percent of such controls were carried out, down from 78 percent in the previous year.

There are still large differences in how often checks are undertaken and how detected deficiencies at food companies, producers, and distributors are handled by authorities. There are also agencies that finance food control in the wrong way, found the report.

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The Public Health Agency of Sweden (Folkhälsomyndigheten) said 101 cases of a certain type of Cryptosporidium parvum had been confirmed in 13 regions of the country.

Patients fell ill from Sept. 25 to Oct. 15 this year and women were more affected than men. Cases range from 4 to 86 years old with an average age of 42. 

Link to salad
The agency added there are another 99 potential cases being investigated. The type of Cryptosporidium parvum involved is common so there could be several possible sources. 

Local infection control units, the Swedish Food Agency (Livsmedelsverket) and Folkhälsomyndigheten investigated the increase in infections to find a source.

Analysis of information from patients on what they had eaten before becoming ill shows they ate mixed or bagged salad more often than a control group.

Salad has a short shelf life so health officials don’t think it is still available for sale but no products have been sampled.

Livsmedelsverket has looked into possible producers and growers but has been unable to find the likely source of infection.

As reported cases of Cryptosporidium have decreased and are at similar levels to previous years, officials believe the outbreak is over.

Salad was also linked to a national Salmonella Typhimurium outbreak that affected 102 people in September and October. Arugula, also known as rocket or rucola, and bagged salad mixes that included arugula were the likely source of infection.

Cryptosporidium in Finland
In October, health authorities in Finland also warned about a Cryptosporidium outbreak that was first noticed in Helsinki.

The Finnish Institute for Health and Welfare (THL) said those sick took part in an organized event at the end of September and since then there had been around 30 cases across the country.

Investigation work includes patient surveys, laboratory sampling, and food tracing. THL does not monitor the occurrence of cryptosporidiosis regularly so local health professionals play a key role in detecting and controlling outbreaks.

Cryptosporidium is a parasite that, if ingested, can cause cryptosporidiosis. Transmission occurs mainly through contact with contaminated water but can be via food or exposure to infected animals or water contaminated by the feces of infected animals. The risk of infection can be reduced by good hand hygiene.

The main symptom is watery diarrhea, which can range from mild to severe. It is often accompanied by stomach pain, nausea or vomiting, fever, and sometimes dehydration. Symptoms usually appear two to 10 days after infection and last one to two weeks.

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A total of 61 people have been confirmed as being infected by the same certain type of Cryptosporidium parvum. These people fell ill from Sept. 25 to Oct. 10 and live in 10 different regions of the country.

Of confirmed cases, 41 are women and 20 are men. They are aged between 11 and 86 years old with an average age of 44.

There are another 98 possible infections that have been reported within the same period and some of these may also belong to the outbreak.

The Public Health Agency of Sweden (Folkhälsomyndigheten) said the increase is under investigation but could be caused by food with wide distribution in the country.

Local infection control units, the Swedish Food Agency (Livsmedelsverket) and Folkhälsomyndigheten are investigating the outbreak to identify the source of infection.

Cryptosporidium is a parasite that, if ingested, can cause cryptosporidiosis. Transmission occurs mainly through contact with contaminated water but can be via food or exposure to infected animals or water contaminated by the feces of infected animals.

The main symptom is watery diarrhea, which can range from mild to severe. It is often accompanied by stomach pain, nausea or vomiting, fever, and sometimes dehydration and weight loss. Symptoms usually appear two to 10 days after infection and last one to two weeks.

Salmonella outbreak looks to be ending
Meanwhile, a Salmonella Typhimurium outbreak has grown again with 84 people now affected, up from the 54 cases in mid-October.

The ill people fell sick between Sept. 17 and Oct. 6. They live in 20 of the country’s 21 regions.

Patients are between the ages of 4 to 87 with an average age of 48 years old. The majority are women with 52 cases.

Cases have been connected by whole genome sequencing of patient samples. This means they are suspected of having been infected by a common source.

Officials reported that the number of suspected and confirmed infections has decreased in recent days, indicating the outbreak is coming to an end. This, as well as the rapid start of the incident and wide geographic distribution of cases, means fresh food with a limited shelf life is suspected of having been the cause.

Work to identify a specific source is ongoing between regional infection control units, the Swedish Food Agency, and the Public Health Agency of Sweden.

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A total of 54 confirmed cases of Salmonella Typhimurium have been reported from 20 different regions in the country from Sept. 17 to Oct. 5.

Patients are aged between 8 and 86 years old; 31 of them are women.

Cases have been connected by whole genome sequencing of patient samples. This means they are suspected of having been infected by a common source, according to the Public Health Agency of Sweden (Folkhälsomyndigheten).

Local infection control units, the Swedish Food Agency (Livsmedelsverket) and Folkhälsomyndigheten are investigating the outbreak to identify the source of infection, which is suspected to be a food with wide distribution in Sweden.

Patient interviews to compile information about what those sick have eaten before falling ill are ongoing. Answers will be used to form a hypotheses about the source and compared to what people in a control group that are not part of the outbreak have eaten.

The incident doesn’t appear to be connected to a Salmonella Typhimurium outbreak that is ongoing in Denmark. Officials believe the outbreak in Sweden is caused by a different source because the strains don’t cluster.

In Denmark, 14 cases have been recorded between Aug. 15 and Sept 16. Patients are seven men and seven women aged between 4 and 84 years old, with a median age of 61. 

The Statens Serum Institut (SSI), Danish Veterinary and Food Administration (Fødevarestyrelsen) and DTU Food Institute are investigating to find the source of the outbreak.

About Salmonella
Food contaminated with Salmonella bacteria does not usually look, smell, or taste spoiled. Anyone can become sick with a Salmonella infection. Infants, children, seniors, and people with weakened immune systems are at higher risk of serious illness because their immune systems are fragile, according to the U.S. Centers for Disease Control and Prevention.

Anyone who has developed symptoms of Salmonella food poisoning should seek medical attention. Sick people should tell their doctors about the possible exposure to Salmonella bacteria because special tests are necessary to diagnose salmonellosis. Salmonella infection symptoms can mimic other illnesses, frequently leading to misdiagnosis.

Symptoms of Salmonella infection can include diarrhea, abdominal cramps, and fever within 12 to 72 hours after eating contaminated food. Otherwise, healthy adults are usually sick for four to seven days. In some cases, however, diarrhea may be so severe that patients require hospitalization.

Older adults, children, pregnant women, and people with weakened immune systems, such as cancer patients, are more likely to develop a severe illness and serious, sometimes life-threatening conditions. Some people get infected without getting sick or showing any symptoms. However, they may still spread the infections to others.

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An opinion article in Svenska Dagbladet said unpasteurized, raw milk is almost impossible to buy in Sweden and the regulations are an example of when state control has good intentions but negative consequences.

Ann-Helene Meyer von Bremen and Martin Ragnar said the rules place too much emphasis on the risks and not enough attention is given to the benefits.

In Sweden, unpasteurized milk cannot be bought in shops but it can be sold or given away from farms directly to the consumer. Farms that want to sell unpasteurized milk must register with their local authority.

Once registered, they can sell up to 70 liters of unpasteurized milk per week to the public. Written information must be provided to consumers saying milk is unpasteurized and that it may contain harmful bacteria. The recommendation is that milk should be boiled or used in dishes that are heat treated before consumption. Children and people with weakened immune systems should not drink the milk without prior heat treatment.

Authority’s view
In reply to the article, Mats Lindblad, from Livsmedelsverket, said it is not true that there is a low risk from drinking unpasteurized milk, as it can contain several different types of bacteria that can make people sick.

E. coli, a bacteria sometimes found in cows, was given as an example. It can have very serious consequences as infection can damage the kidneys of young children and lead to death in severe cases.

One of the main aims of Livsmedelsverket is to ensure that consumers do not get sick from food. Sale of unpasteurized milk is regulated and this is cited as a likely explanation for so few related illnesses in recent years.

The agency said it had looked at both the benefits and risks of drinking unpasteurized milk, acknowledging studies on vitamin content of milk before and after pasteurization and a reduction in allergies in children who grew up on farms. Overall, the assessment is that the risks of unpasteurized milk outweigh any benefits.

Meanwhile, Livsmedelsverket has revealed it closed a company earlier this month due to poor hygiene conditions.

Al Hana Mejeri AB has also been banned from selling food. All food manufactured or sold by the company must be removed from stores and disposed of. People who have any affected items at home were told not to consume them. Items are labeled as Al Hana Mejeri.

The company primarily manufactures dairy products such as yogurt and cheese but also offered items including olive oil. Most products were sold to stores in Skåne, but they may also have been passed on to other companies.

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An investigation into the incident in Gammelstad on Aug. 5 revealed people fell ill after eating spaghetti bolognese from a restaurant in the city of Luleå.

An investigation by officials from Luleå Municipality to determine the cause included studying the symptoms of those affected, interviewing patients, visiting the food company and sampling leftovers.

Food had been prepared at a restaurant the day before the event and stored in a refrigerator. On Aug. 5, it had been reheated for transporting to and serving at the tournament.

Bacillus cereus and Staphylococcus aureus
Testing of the bolognese left at the restaurant was found to be satisfactory. Samples were also taken in Gammelstad where serving took place. High levels of bacteria were detected in the pasta, plus the presence of toxins that can cause food poisoning. Food had been left at room temperature for some time after serving, which provided an opportunity for bacterial growth.

Bacillus cereus and Staphylococcus aureus were found in the pasta meal. Symptoms experienced by those sick matched what would be expected with such contamination.

Staphylococcal food poisoning is caused by eating foods contaminated with toxins produced by the Staphylococcus aureus bacteria. If this bacteria ends up in food that is stored at the wrong temperature for too long, it can multiply and form a heat-resistant toxin that can make people sick.

Based on the short period from when food was delivered to people eating it, officials said it was likely that bacteria were present before delivery. However, from information provided by the restaurant it was not possible to pin down how such bacterial and toxin growth occurred.

To increase knowledge about such outbreaks, follow-up analyses will be carried out at Livsmedelsverket (the Swedish Food Agency) and further controls of the business will be done by authorities.

Histamine in fish again
Meanwhile, 20 people fell sick recently in Sweden due to histamine levels in fish. The foodborne outbreak was linked to tuna from Vietnam.

In April 2021, 19 people were affected by histamine poisoning in Stockholm after eating tuna loins from Vietnam at three different restaurants.

In 2020, there were three outbreaks of histamine poisoning in tuna from Vietnam in three months. These incidents affected about 60 people but contaminated tuna came from different batches. Patients were from different areas in southern and central Sweden.

Onset of histamine food poisoning symptoms can range from minutes to several hours following ingestion of the toxin. Typically, the average incubation period before illness is one hour.

The most common symptoms of histamine, also known as scombroid fish poisoning, are tingling or burning sensation in the mouth, facial swelling, rash, hives and itchy skin, nausea, vomiting or diarrhea. They usually resolve within several hours without medical intervention.

Production of histamine is related to mishandling of food because of storage at incorrect temperatures. Once produced, histamine cannot be eliminated by normal cooking or freezing temperatures.

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The report by the National Veterinary Institute (SVA), Folkhälsomyndigheten (the Public Health Agency of Sweden), Livsmedelsverket (the Swedish Food Agency) and Jordbruksverket (Swedish Board of Agriculture) showed a rise for Campylobacter, Salmonella, Listeria, E. coli and Yersinia infections.

Disease surveillance relies on patients seeking care and fewer people have done this during the pandemic. This is believed to be related to patients with symptoms choosing to not seek care and a true reduction in disease incidence because of changes in general hygiene such as increased handwashing, physical distancing and reduced travel because of COVID-19-related recommendations, according to the agencies.

Rise in Campylobacter cases and Salmonella outbreaks
A total of 4,059 cases of campylobacteriosis were reported in 2021 and 3,025 were domestic compared to 3,434 cases overall in 2020.  

Incidence of domestic cases in 2021 increased by 23 percent from the year before. The rate of travel-related cases was at a record low, which makes the overall incidence the second lowest since the reporting system was introduced in 1997.

A large increase in people infected with Campylobacter was noticed in June with a peak in July-August. Also, in the surveillance program for chickens, a higher prevalence was noted from July through October. Most cases have been considered sporadic, but recent work has found many are part of outbreaks, which are often linked to poultry meat.

A total of 946 cases of salmonellosis were reported, compared to 826 in 2020 and 1,993 in 2019. Domestic cases increased from 422 in 2020 to 722 in 2021.

The most common types in domestic patients were Salmonella Enteritidis, monophasic Salmonella Typhimurium and Salmonella Typhimurium. Another 60 different serovars were identified in 2021.

Eleven outbreaks involving 10 or more cases were recorded, up from 2020 when only two such outbreaks occurred. These outbreaks accounted for 293 of the 722 domestic infections.

An outbreak of Salmonella Enteritidis linked to chocolate wafers was investigated where 19 of 34 cases were younger than 10 years old. The outbreak strain was identified in two of 22 analyzed samples of products from cases’ homes. Neither the company that made the wafers nor the control authority could find any Salmonella in the production line or the product.

Salmonella Coeln affected 53 people with sprouts as the suspected source and Salmonella Dublin has sickened 22 people between September 2019 and the end of 2021.

Sweden had 48 cases in the multi-country Salmonella Braenderup outbreak linked to melons from Honduras and 42 cases linked to six serotypes and eight different strains of Salmonella in the outbreak from tahini and halva produced in Syria.

More E. coli and Listeria cases recorded
In 2021, 653 cases of E. coli were reported and 530 were domestically acquired, compared to 491 overall cases in 2020.

STEC-associated Hemolytic Uremic Syndrome (HUS) was reported in 24 cases of which 23 were domestic infections in 2021. 16 HUS cases were children younger than 10.

In total, 80 different serotypes were identified. The most common types were O157:H7, O103:H2 and O26:H11.

Three outbreaks had cases spread across the country where the source was suspected to be food, but no source could be identified. Two were O157 and one was O103.

In total, 107 Listeria infections were reported compared to 88 in 2020. The median age was 78 and as in previous years, most cases were in the over 80’s age group. A total of 21 people died within one month of diagnosis.

In 2021, five cases of Listeria monocytogenes were linked to a cluster of 14 cases in Belgium. They were reported between 2014 and 2021 and the outbreak strain was detected in salmon from Norway. For Swedish cases, salted non-heat-treated salmon was the suspected source of infection.

The source of an outbreak with two cases was traced to a meat plant. One person had eaten a locally produced sausage. The outbreak strain was found in samples from equipment and processing areas. One cluster included 10 cases from 2021 and eight from 2019 but a source was not found.

Another case was linked to a local cheese. A sample of washed rind cheese from the refrigerator of the patient was positive for the outbreak strain. Cheese was made from pasteurized milk, but analysis of cheese and environmental samples from the dairy showed the premises was contaminated by the outbreak strain and it was isolated from a washed rind and a semi-hard cheese.

Yersinia, Cryptosporidium and Brucella
During 2021, 313 Yersinia infections were reported with the majority falling sick in Sweden versus 220 cases in 2020.

Sixteen people were ill after eating iceberg lettuce at a restaurant chain in early 2021.

A total of 524 cryptosporidiosis cases were recorded. Most people were infected in Sweden but 83 fell sick abroad. A total of 42 domestic cases were reported in January because of an outbreak that had vegetables as the suspected source.

In January, several illnesses were detected in a retirement home followed by cases in March among students and staff at two different schools in Jönköping county. Fourteen cases were positive for Cryptosporidium parvum. Kale and cabbage were suspected as the probable cause of infection. Kale was positive for Cryptosporidium parvum. Fecal matter from rodents and deer at the farm was sampled, but the source of contamination of vegetables was not established.

In 2021, 10 cases of brucellosis were reported. Patients had an age range of 25 to 78 years old and four were female. Two people acquired the infection in Iraq, two in Somalia, one in Afghanistan and one in Ethiopia and for three country of infection was unknown. For five cases, unpasteurized dairy products were the likely source of infection.

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Research also found the majority of Campylobacter infections in patients infected abroad were resistant to antibiotic groups that are important in healthcare. However, no bacteria from meat or patients were resistant to a group called macrolides that are the first choice to treat severe infections. This group includes azithromycin and erythromycin.

Antimicrobials – including antibiotics – are medicines used to prevent and treat infections in humans and animals. Antimicrobial resistance (AMR) occurs when bacteria, viruses, fungi and parasites no longer respond to medicines making infections harder to treat.

The Swedish Food Agency (Livsmedelsverket) and Public Health Agency of Sweden (Folkhälsomyndigheten) investigated how common it was for Campylobacter from chicken meat in stores and in patients to be antibiotic-resistant. A total of 284 isolates from patients and 111 from chicken meat were included in the study.

Sweden generally has a lower use of antibiotics for both humans and food-producing animals compared with other countries. Most people with a Campylobacter infection recover after about a week and antibiotics are given only in severe and long-term cases.

The work found 85 percent of Campylobacter from Swedish chicken meat and 58 percent from foreign meat were sensitive to important antibiotic groups.

A total of 76 percent of people infected in Sweden had Campylobacter that was not resistant to front line antibiotics but for those infected abroad the figure was 21 percent.

Results for meat
The same types of resistance markers to the clinically important classes of antibiotics quinolones, tetracyclines and aminoglycosides were found in Campylobacter jejuni from chicken meat and patients.

Following a large outbreak linked to domestic chicken meat in 2016-17 the Public Health Agency of Sweden and Swedish Food Agency genetically compared Campylobacter from retail chicken meat and Swedish patients. Similar smaller outbreaks were recorded in 2018 and 2020.

In 67 of the 79 isolates of Campylobacter jejuni from Swedish chicken meat, no mutations or genes encoding resistance to the important classes macrolides, quinolones, tetracyclines, or aminoglycosides, were identified. However, 14 of 24 isolates from meat from other countries lacked such resistance determinants.

For Campylobacter jejuni from Swedish, conventionally bred chicken, 40 of 45 isolates lacked genes or mutations for resistance to quinolones, macrolides, tetracyclines or aminoglycosides. For the 34 isolates from organic Swedish meat, 27 didn’t have such resistance markers.

A total of 87 different sequence types were detected in the 375 isolates of Campylobacter jejuni from chicken meat and patients.

Findings from patients
For Campylobacter jejuni from patients, 162 of the 212 isolates from domestically acquired infections and 11 of 53 isolates from travel-related cases contained no such signs of resistance.

Multidrug resistance was identified in only three isolates from patients, two of whom had likely been infected abroad.

The most common resistance determinant in isolates from chicken meat and patients was genes for resistance to beta-lactams, which are not recommended to treat Campylobacter infections. The main resistance type identified among the clinically important antibiotic classes was a mutation, which confers resistance to quinolones, followed by a tetracycline resistance gene and an aminoglycoside resistance gene.

The aim of the study was to increase knowledge about the resistance situation of Campylobacter in Sweden and to get a basis for source attribution, risk assessment and management regarding the pathogen in chicken meat.

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Food categories behind illnesses included bakery items with 210 cases, chicken with 155 people sick and foods from the sea at 164 cases. Bakery products such as cakes were a source of infection in outbreaks of norovirus and Shiga toxin-producing E. coli (STEC) with 200 and 10 cases, respectively.

Campylobacter in chicken was behind 155 cases. When the source of infection was food from the sea, norovirus in oysters caused 124 illnesses, followed by Vibrio parahaemolyticus in seagrass with 50 sick and histamine in fish with 34 cases.

A new online form for recording incidents launched in January 2020 to raise the quality of data. Municipal control authorities, the County Administrative Boards, and Public Health Agency of Sweden (Folkhälsomyndigheten) conduct epidemiological investigations of foodborne outbreaks and send results to the Swedish Food Agency.

Causes of outbreak and illness decline
There were 173 reports of suspected or confirmed food poisoning with 1,314 cases of illness. In 160 reports, two or more people were infected from the same source.

Compared to 314 outbreaks with 2,835 cases in 2019, the number of reports and illnesses almost halved in 2020. This reduction might have been because of restrictions and recommendations introduced during the COVID-19 pandemic. For example, there were fewer people using restaurants, better hand hygiene among food handlers, and public events where food might have been served were cancelled.

For most reports, the cause was unknown, however for 44 percent of reported cases, some type of virus was cited. This is due to 23 outbreaks with 571 illnesses. Norovirus caused 22 food poisoning outbreaks with 513 cases, Campylobacter was behind four outbreaks with 158 cases and Vibrio parahaemolyticus was associated with one outbreak of 50 patients.

Histamine caused 10 outbreaks, while STEC, Salmonella, Cryptosporidium and Listeria monocytogenes were responsible for a few incidents.

Food poisoning reports were highest between January to March in 2020, with 63 reports and 634 cases of illness. This is due to several oyster-related outbreaks and because fewer events occurred during the rest of the year because of pandemic-related measures, according to the report.

A previous report on infectious diseases in animals and humans found an overall decline in foodborne infections in Sweden in 2020.

Factors behind contamination
For almost two-thirds of cases reported to the Swedish Food Agency, the source was food contaminated early in the production chain, such as in industrial facilities, from there the food was widely distributed to industry or primary production. To reduce the number of poisonings, it is important to have good systems for food safety in primary production and such facilities, said officials.

The most commonly mentioned contributing factor was incorrect storage with respect to time and temperature. This may refer to inappropriate temperature when keeping food heated, or it not be held at low enough temperatures in cold storage. The next most common issue was a contaminated ingredient.

Reporting information on country of origin of contaminated food is optional. Examples of outbreaks traced to countries outside Europe include nine outbreaks from tuna, one of norovirus from frozen raspberries and one with Vibrio parahaemolyticus from seagrass. A number of norovirus outbreaks were linked to oysters from France and some outbreaks were traced to Swedish products.

Climate change impact
Meanwhile, a new analysis from the Public Health Agency of Sweden shows how health in the country could be affected by climate change.

The risk and vulnerability analysis describes 17 different risks based on the estimated probability between 2021 and 2050, different health consequences and current vulnerability and capacity.

The greatest risks to health, in relation to severity and probability, are heat waves and tick-borne diseases. There is a high probability that climate change may lead to poorer drinking water quality and an increase in water- and foodborne infections, according to the report.

Climate change can increase the risk of foodborne infection through a higher risk of contaminated irrigation water being used on fruits and vegetables in Sweden and also via imported food.

During the hot summer months, infectious agents have more favorable conditions for growth and illnesses are often reported because of inadequate handling of food in warmer weather. For example, more people have picnics and barbecues but food handling, cold storage and hygiene advice is not always followed. This means expected longer and warmer summers could result in more people being sick.

The Swedish Food Agency also recently looked at how climate change could affect microbiological food safety in the future, finding the prevalence of most hazards would probably increase.

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In October, 40 people became ill with monophasic Salmonella Typhimurium with the majority falling sick in the first half of the month. An earlier update identified 33 patients. Cases were linked by whole genome sequencing.

As no new illnesses have been recorded after late October, the outbreak was recently judged to be over by authorities.

Sick people were 2 to 92 years old with a median age of 44. They lived in eight different regions.

Infection control units, the Swedish Food Agency (Livsmedelsverket) and Public Health Agency of Sweden (Folkhälsomyndigheten) were part of the investigation.

Information on possible sources of infection was collected via interviews as well as surveys and purchase receipts from patients to try to identify common foods that were consumed or purchased.

Despite an analysis of this information, and comparisons with what people who were not part of the outbreak had eaten, it was not possible to identify any potential vehicle of infection.

Officials believe the source was a food with a wide distribution that had been on the market for a limited time due to the geographical spread of patients and the fact that people fell ill in the space of a month.

US. other countries impacted by Salmonella outbreak from tahini and halva
The Public Health Agency of Sweden has also reported another five people sick as part of a multi-country outbreak linked to tahini and halva from Syria. Since July 2019, 41 people have been sickened by several different types of Salmonella.

The United States has reported six Salmonella Mbandaka cases, one in 2020 and the rest this year. Canada has eight confirmed cases: five of Salmonella Mbandaka, two of Salmonella Havana and one of Salmonella Orion from 2019 to 2021. Cases of Salmonella Kintambo, Salmonella Havana and Salmonella Senftenberg can be linked to findings in tahini and halva sampled in Germany, the United States and Norway respectively.

In Europe, at least 121 people have been affected since January 2019, mostly in Germany but also in Denmark, Norway and the Netherlands.

In Sweden, the latest patient fell sick in October 2021. In total, ill people live across 12 regions. The patients are 0 to 88 years old with a median age of 33 and 13 are children under 5. Slightly more men than women have been ill. Fourteen people have been infected with two types of Salmonella Havana, 13 with Salmonella Mbandaka, seven by Salmonella Kintambo, four with Salmonella Orion and three by two types of Salmonella Senftenberg.

Testing in Sweden has found Salmonella Havana, Salmonella Mbandaka, Salmonella Orion and Salmonella Senftenberg in tahini or halva that are linked to patients in the outbreak by whole genome sequencing. Other Salmonella types have also been identified in products that were likely sold in smaller specialty stores.

Despite a number of product recalls, authorities are concerned that because of the long shelf life, there is a risk that consumers may still have contaminated items at home and more people will fall ill.

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The report also looks at the hazards that may become relevant in different food types as a result of climate change, with a focus on Swedish conditions, and discusses how they could be controlled. The section covers dairy, meat, fish and seafood, eggs, cereal products and fruits, berries and vegetables.

A risk profile was developed to increase knowledge on how climate change can affect microbiological food safety in the future. The focus was to identify existing and emerging hazards that may be of concern and impact the safety of food and water consumed in Sweden.

The report also proposes ways to meet the new challenges posed by changing normal conditions and an increased frequency of extreme events.

Although there are knowledge gaps, the analysis shows the prevalence of most microbiological hazards would probably increase as a result of climate change. Conclusions on the change in specific hazards as well as the extent and speed of the impact are uncertain and depend on accuracy of climate scenarios and what mitigation measures are put in place.

Swedish situation
In Sweden, the climate will become warmer, especially in winter. Rainfall will generally increase, mostly in winter and spring, especially in northern parts of the country. In the southeast, increased drought and water shortages are predicted. Climate change is also expected to lead to more frequent extreme weather such as floods and heatwaves.

A change in normal conditions can increase the presence of certain bacteria, viruses, parasites and mold toxins that can cause disease via food and drinking water. Extreme weather events can lead to power outages, disruptions to infrastructure and food contamination.

Impacts on the environment and society that can affect food safety include changing conditions for plant cultivation, animal production, infrastructure, energy supply, and water availability, according to the report.

Data is based on scientific literature and reports from domestic and international agencies including the Swedish Meteorological and Hydrological Institute, European Food Safety Authority (EFSA), and the Food and Agriculture Organization (FAO) of the United Nations.

“The report from the Swedish Food Agency shows what science says today about how climate change may affect food production in Sweden and the food we import. What we have come up with also provides a basis for continued work on how we can tackle the new challenges,” said Jonas Toljander, a risk assessor.

Likely increase in hazards
Bacteria that are likely to increase in the environment, water, animals, plants, and/or food raw materials because of a changing climate, and for which the level of evidence is judged to be high, are Bacillus anthracis, Francisella tularensis, Salmonella, Shigella, and Vibrio. There is also some evidence that Campylobacter, Listeria and Shiga toxin-producing E. coli (STEC) may become more common.

All foodborne viruses have the potential to increase in incidence because of climate change. However, the level of evidence is medium for norovirus and low for hepatitis A and E viruses.

Most parasites are considered able to grow more but the level of evidence is mostly low. For Cryptosporidium, Giardia intestinalis, and Toxoplasma gondii, it is medium.

Among the mycotoxins, it is estimated that all Fusarium toxins covered (DON, T2/HT2, zearalenone, and fumonisins) will increase, of which the evidence level is highest for deoxynivalenol (DON) and fumonisins. Aflatoxins are also expected to become more prevalent.

Microbiological hazards emerging because of a changing climate are likely to vary for different food groups and stages in the supply chain.

The Swedish Food Agency has previously published documents touching on climate change including a handbook to help drinking water producers adapt supply to changed climatic conditions in 2019 and a plan for the food sector in a changing climate in 2018.

“It is important to start adapting the food chain based on a changing climate so that we can maintain the high degree of food safety that we have today,” said Annica Sohlström, director general of the Swedish Food Agency.

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From the end of August to October, 52 people from 14 regions were found with the same type of Salmonella Coeln thanks to whole genome sequencing. This means it is likely they were infected by a common source.

Salmonellosis cases were aged 0 to 85 years old with a median of 35. Overall, 27 females and 25 males were sick.

As there have been no new cases or samples of the outbreak strain from patients since Oct. 26, public health officials believe the outbreak has ended.

Sprouts suspected but not confirmed as source
Local infection control units and municipalities helped in the investigation with the Swedish Food Agency (Livsmedelsverket) and Public Health Agency of Sweden (Folkhälsomyndigheten).

A previous update, when the source had not been found, was given when 31 people were ill. The number of people affected by Salmonella Coeln in Sweden in 2020 and 2019 was in single figures.

The Public Health Agency of Sweden conducted a case-by-case study based on questionnaires by regional infection control units that had Salmonella patients. These people answered questions about what they had eaten during the week before illness as part of the epidemiological investigation.

Responses from outbreak patients were compared to answers from Salmonella cases that did not belong to the outbreak. This found a link between illness with the outbreak strain and consumption of sprouts. A suspected link to sprouts had also been identified during investigations in one region.

It is believed that a suspected contaminated batch was delivered to grocery stores, wholesalers and commercial kitchens at the end of August.

Sampling and analysis of remaining sprouts from ill people and from production did not find Salmonella, so suspicions that they were the source of infection could not be confirmed by microbiological analyzes.

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The national monophasic Salmonella Typhimurium outbreak has affected 33 people. Whole genome sequencing has shown that patients have the same strain of Salmonella Typhimurium, so are suspected of having been infected by a common source of infection.

Affected local infection control units, the Swedish Food Agency (Livsmedelsverket) and the Public Health Agency of Sweden (Folkhälsomyndigheten) are investigating the outbreak.

The source of infection has not been found but is believed to be a food with a wide distribution in Sweden.

Cases range in age from 2 to 89 years old with a median age of 29. They live in seven different regions of Sweden.

Sixteen people younger than age18 and 13 more older than 60 have been infected. Women make up 21 cases and 12 men are ill.

Monophasic Salmonella Typhimurium was in the top three for the causes of Salmonella patients infected in Sweden in 2020.

Campylobacter levels back to normal
Meanwhile, the number of people getting sick from Campylobacter has returned to normal levels after increasing twice.

A rise in the number of Campylobacter infections was seen from the beginning of July until mid-August when 179 to 191 cases were reported per week.

After one month of gradual decline, the number of reported cases increased again in late September and early October before going back down once more. This pattern was seen across the country.

The spike in human cases was preceded by an increase of Campylobacter in broiler flocks, according to data from the National Veterinary Institute (SVA).

Previous studies have shown that infections are often linked to insufficiently cooked chicken. Officials believe it is likely that the increased presence of Campylobacter in chicken flocks was behind the rise in human cases.

The Public Health Agency of Sweden has collected some samples from cases within the microbiological monitoring program to identify potential common sources of infection. Other work involves comparing the types of Campylobacter detected in patients with those found in chickens.

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From late August up to mid-September, 31 people across the country have fallen sick with Salmonella Coeln infections.

The source of infection is suspected to be a food with a wide distribution in Sweden.

Whole genome sequencing has shown patients had the same type of Salmonella Coeln, which means it is likely they were infected by a common source.

Those sick range in age from 0 to 85 years old with a median age of 28. They live in 12 different regions in Sweden and 18 are men.

Local infection control units and municipalities are involved in the outbreak investigation with the Swedish Food Agency (Livsmedelsverket) and Public Health Agency of Sweden (Folkhälsomyndigheten).

The number of people affected by Salmonella Coeln in Sweden in 2020 and 2019 was in single figures.

About Salmonella
Food contaminated with Salmonella bacteria does not usually look, smell, or taste spoiled. Anyone can become sick with a Salmonella infection. Infants, children, seniors, and people with weakened immune systems are at higher risk of serious illness because their immune systems are fragile, according to the CDC.

Anyone who has developed symptoms of Salmonella food poisoning should seek medical attention. Sick people should tell their doctors about the possible exposure to Salmonella bacteria because special tests are necessary to diagnose salmonellosis. Salmonella infection symptoms can mimic other illnesses, frequently leading to misdiagnosis.

Symptoms of Salmonella infection can include diarrhea, abdominal cramps, and fever within 12 to 72 hours after eating contaminated food. Otherwise, healthy adults are usually sick for four to seven days. In some cases, however, diarrhea may be so severe that patients require hospitalization.

Older adults, children, pregnant women, and people with weakened immune systems, such as cancer patients, are more likely to develop a severe illness and serious, sometimes life-threatening conditions. Some people get infected without getting sick or showing any symptoms. However, they may still spread the infections to others.

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People who received food from the kitchen at Allégården in the Sunne municipality fell ill with gastrointestinal problems between Aug. 18 and 27. Allégården has more than 60 apartments for people older than 65.

Samples were taken from seven people with suspected Campylobacter infections and a few of them were found to be positive, according to officials.

Campylobacter is a reportable disease and officials were contacted on Aug. 26 to investigate the incident with the help of infection control experts from Värmland and Livsmedelsverket (Swedish Food Agency).

Authorities carried out food controls in the kitchen at Allégården on two occasions including sampling on the first visit. Test results showed no presence of Campylobacter. As there was no food left from the time of illnesses, it was not possible to take more samples.

Officials were not able to determine whether the spread of infection was caused by food that had been contaminated before arrival at the kitchen, by deficiencies in handling, or because of a lack of hygiene.

Operators at Allégården will review and improve their routines to ensure such an outbreak does not happen again, according to officials.

Link to wider issue
The outbreak could be part of the wider problem affecting the country.  In late August, Folkhälsomyndigheten (the Public Health Agency of Sweden) reported a rise in people getting sick from Campylobacter.

Since the end of July, the number of people infected was between 160 and 200 per week. The increase had been seen throughout the country and in all age groups.

The spike in human cases came after an increase of Campylobacter in broiler flocks, according to data from the National Veterinary Institute (SVA).

An increased presence of Campylobacter in chickens for meat production is suspected to be linked to the rise in human cases.

Folkhälsomyndigheten is collecting samples from patients for analysis and typing as part of the microbiological monitoring program to identify any common sources of infection.

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Reports of Campylobacter, cryptosporidium, E. coli, Listeria, Salmonella and Yersinia infections all declined in the past year with at least some of the drop attributed to the direct and indirect consequences COVID-19 has had on surveillance efforts and results.

Disease surveillance is driven primarily by people seeking care and during the pandemic fewer patients have gone to primary care doctors with symptoms consistent with common zoonoses. This is thought to be related to patients choosing to not seek care and a true reduction in disease incidence related to changes in general hygiene such as increased handwashing, physical distancing and reduced travel because of coronavirus related recommendations.

The report was prepared by the National Veterinary Institute (SVA) with help from Folkhälsomyndigheten (the Public Health Agency of Sweden) and Livsmedelsverket (the Swedish Food Agency).

Record Campylobacter low
The pandemic resulted in a record low of campylobacteriosis and a record high proportion of domestic infections. A total of 3,434 cases were reported, which was down from 6,693 in 2019.

A large rise in the number of people infected with Campylobacter was noticed in early August. In parallel to this, several infections were observed in abattoir employees at a large slaughterhouse. There had also been an increase in the proportion of Campylobacter positive batches of chicken from the second half of July, mainly among flocks sent to the slaughterhouse.

One reason cited for the spread among poultry flocks was dirty transport cages that carried the bacteria between chicken farms. A factor that may have made it easier for Campylobacter to gain a foothold at the farms is the practice of thinning, according to the report.

Multi-year Listeria concerns
During 2020, the incidence of listeriosis decreased compared to 2019 but the overall picture shows an increasing trend. In total, 88 confirmed cases were reported compared to 113 in 2019. Overall, 23 people died within one month from diagnosis.

Fourteen different clusters were identified of which 13 contained identical or closely related isolates already seen before 2020. One listeriosis cluster included 19 cases with identical or nearly identical isolates identified since 2014 of which eight cases were in 2020. The majority are from two counties in northern Sweden which indicates the source of transmission is a locally made food product. Additional sampling at several producers was unable to find the outbreak strain.

Another cluster included 26 cases with the same or similar isolates found since 2011 of which four cases were in 2020. The outbreak strain was found in blue cheese and ham sampled from the refrigerators of two patients in 2020, but the source is still unknown.

A rare strain of Listeria monocytogenes in Sweden caused one illness linked to a locally produced cheese. A sample of washed rind cheese was collected from the refrigerator of the person and tested positive for the outbreak strain. The cheese was made from pasteurized milk. Analysis of environmental samples from the dairy showed the site and equipment were contaminated by the outbreak strain.

Salmonella illness from domestic beef
A total of 826 cases of salmonellosis were reported, compared to 1,993 in 2019. Domestic cases decreased by 45 percent from 763 in 2019 to 422 in 2020. The sharp decrease in domestic cases and the record low incidence likely reflects changes in behavior related to the pandemic.

The most common serovars among domestic infections were Typhimurium, Enteritidis and monophasic Typhimurium. Another 55 serovars were identified during 2020.

An increasing number of Salmonella infections linked to domestic beef have been observed. Between 2019 and early 2021, 27 cases belonging to four different outbreaks involving the serovars Agona, Dublin, Düsseldorf, and Reading have been investigated.

Five cases with Salmonella Newport from late autumn were linked to an outbreak investigated by Norwegian authorities. The probable source of infection was iceberg lettuce.

Only two outbreaks affected more than 10 people. One was caused by monophasic Salmonella Typhimurium, in which 17 people fell ill between September and November but the source of infection was unknown. The second was caused by the same types of Salmonella Typhimurium as were found among wild birds, cats and dogs and affected 20 people including 12 children.

Long term STEC rise
In 2020, 491 E. coli cases were reported of which 396 were domestically acquired. The long-term trend for STEC infection in Sweden is rising but the figure fell from 756 in 2019.

Shiga toxin producing-E. coli (STEC)-associated hemolytic uremic syndrome (HUS) was reported in 10 cases of which eight were domestically acquired. Six HUS cases were children younger than the age of 10.

For 56 percent of the domestically acquired STEC cases, an isolate could be serotyped. However, for the travel associated cases only 37 percent were typed. In total, 68 different serotypes were identified. The most common were O26:H11, O157:H7 and O103:H2.

One national outbreak investigation was performed during 2020 with seven cases of O103:H11 but no source could be identified.

Other pathogens
A total of 641 cases of cryptosporidiosis were reported with more than 550 infected in Sweden. This is down from more than 1,000 infections in 2019. Many cases in January were a continuation of a national increase from late 2019 where different vegetables as sources of infections were investigated.

During 2020, 220 Yersinia infections but no outbreaks were reported. This is the lowest incidence since at least 1997 and down from 393 in 2019.

Seven cases of brucellosis were reported, which is less than the average of 13 in the past 10-year period. The low number can partly be explained by a reduction in travel abroad because of the pandemic so less imported infections. For three cases, unpasteurized dairy products were the probable source of infection.

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Between late December 2020 and early April 2021, 32 people living in 15 counties fell ill after infection with the same type of Salmonella Enteritidis. Nineteen patients were children under the age of 10 while nine people were above 70 years old. Seventeen females and 15 males were affected.

The outbreak was investigated by local infection control units, National Food Agency (Livsmedelsverket) and the Public Health Agency of Sweden (Folkhälsomyndigheten) with the first update in February when 12 people were sick.

Through the national microbial surveillance program, the Public Health Agency of Sweden identified several cases infected with the same type of Salmonella Enteritidis.

Local infection control units interviewed sick people about what they ate and where they bought food from before they became sick. This identified the suspected source of infection as a kind of chocolate wafer sold in Axfood stores.

In analyzes by the National Food Agency, Salmonella was identified in chocolate wafers of the Eldorado brand. Axfood issued a recall of the batch in question, which came from Poland.

Further testing showed the isolate from chocolate wafers was the same type as that found in patients which determined the source of infection.

The recall applies to Eldorado chocolate wafers 415-gram with a best before date of Sept. 15, 2021 and batch number 350.3 E400:56. Axfood urged consumers who bought the product in question to return it to the store where it was purchased.

“We take this extremely seriously, and are now investigating with the supplier how it could have happened and how we can ensure that something similar does not happen again,” said Axfood’s Quality Manager Susanna Wadegård.

Impact of COVID-19 measures on foodborne infections
Meanwhile, a decline in many diseases in Sweden this past year, including foodborne infections, has been linked to measures put in place during the COVID-19 pandemic.

Factors contributing to the fall included people following advice and recommendations, having fewer close contacts and gatherings, keeping their distance, avoiding travel abroad and increased attention on hand hygiene. The reduction in healthcare visits in 2020 may also have affected the incidence of certain infections.

The number of Campylobacter infections decreased for the fourth year in a row despite a large outbreak during the summer and autumn caused by contaminated chicken. The figure was almost 6,700 in 2019 and it was 3,429 in 2020.

Salmonella infections went down from nearly 2,000 in 2019 to 826 in 2020, EHEC fell from 755 in 2019 to 491 in 2020; Yersinia declined from 393 in 2019 to 221 in 2020; Listeriosis went from 113 in 2019 to 88 in 2020 and Cryptosporidium dropped from 1,088 to 638.

Detailed reports on each infectious agent will be published later this year. A further aim is to do a more thorough evaluation of the effects from the pandemic on other diseases.

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The foodborne outbreak at the beginning of April affected 19 people in Stockholm.

Guests eating tuna at three different restaurants in Stockholm reported symptoms of histamine poisoning.

All three restaurants purchased frozen tuna loins with the same expiry date from the same supplier, indicating that high levels of histamine occurred before the tuna was brought into Sweden from Vietnam via the Netherlands.

Recurring issue
In March, Italian authorities reported an outbreak caused by histamine in frozen yellowfin tuna loins from Vietnam, via the Netherlands but did not say how many people were affected.

In 2020, Sweden recorded three outbreaks of histamine poisoning in tuna from Vietnam in three months.

These outbreaks affected about 60 people but were not directly related as the tuna originated from different batches. Patients were from different areas in southern and central Sweden.

Onset of histamine food poisoning symptoms can range from minutes to several hours following ingestion of the toxin. Typically, the average incubation period before illness is one hour.

The most common symptoms of histamine, also known as scombroid fish poisoning, are tingling or burning sensation in the mouth, facial swelling, rash, hives and itchy skin, nausea, vomiting or diarrhea. They usually resolve within several hours without medical intervention.

Production of histamine is related to mishandling of food because of storage at incorrect temperatures. Once produced, histamine cannot be eliminated by normal cooking or freezing temperatures.

New rules and Salmonella study
Meanwhile, new legislation has come in from this month in Sweden that includes food control authorities being able to make purchases without disclosing their identity as an official agency until afterward. This makes it easier to check that food on the market is what it claims to be, does not mislead consumers, and that it is not harmful to health.

It applies to distance purchases such as e-commerce and to physical stores. Previously, there had been no support in law for authorities to act without making themselves known. The changes were made to bring domestic rules into line with EU regulations.

Finally, the government has commissioned the Swedish Board of Agriculture and Swedish Veterinary Institute to do a feasibility study on measures to effectively prevent and manage the presence of Salmonella in farm animals.

In the past year, the number of Salmonella cases has increased in food-producing animals and in pig herds. This leads to increased costs for animal owners and the state in combating outbreaks.

The work will investigate possible sources of infection and include new knowledge on analysis methods. Findings will be reported by the end of January 2022.

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From January until the beginning of February this year, twice as many people fell ill with Yersinia infection as did during the same period in a normal year.

From 53 cases of Yersinia enterocolitica, 33 lived in Stockholm, Västra Götaland and Halland. Isolates from 24 of these cases were typed by whole genome sequencing and 16 outbreak patients with clustered isolates of sequence type 18 could be identified.

Of these 16, eleven were women and five were men aged 7 to 34 years old. All fell ill between Jan. 4 and 18.

Managing resources
Rikard Dryselius, a microbiologist at Folkhälsomyndigheten (Public Health Agency of Sweden), said collection and typing of Yersinia isolates is not done routinely in the country.

“Instead, individual counties can ask for help with typing Yersinia when they see a need. Alternatively, we may ask the laboratories to send in isolates if we see an increase in cases nationally that should be investigated,” he said.

“Due to the strained situation for infection control units and clinical laboratories during the pandemic, we chose to request interviews/questionnaire responses and collection of isolates only from the counties where the increase was highest. It is therefore very likely that there were more than 16 outbreak cases but the lack of additional isolates to sequence means that we cannot confirm this.”

Folkhälsomyndigheten, infection control units in the Stockholm, Västra Götaland and Halland regions and Livsmedelsverket (Swedish Food Agency) investigated the incident.

Health officials interviewed sick people and compiled questionnaire responses about what and where they ate before illness onset.

A case-case study where questionnaire responses from outbreak cases were compared with answers from people with Yersinia infection that did not belong to the outbreak was done.

Restaurant and iceberg lettuce link
The investigators found the outbreak cases had, to a greater extent, visited a certain restaurant chain. Follow-up interviews about what they had eaten led to iceberg lettuce being suspected as the source of infection.

According to the trawling questionnaire sent to outbreak cases, seven out of 12 mentioned they had visited the restaurant chain before falling ill while seven out of 72 cases with yersiniosis who responded to the same questionnaire in 2019 mentioned that they had done so.

The suspicion of a contaminated batch of iceberg lettuce distributed to a restaurant chain was strengthened by the outbreak timeline, which suggested that a product with a wide geographical spread and a limited shelf life was the underlying cause.

Sweden has no significant production of iceberg lettuce at this time of year and attempts are being made to trace the country of origin.

Meanwhile, investigations are ongoing to find the source of a Salmonella Enteritidis outbreak in the country. It is not related to the Salmonella outbreak in Norway linked to meat from Germany.

The first person fell ill at the end of December 2020. There are 25 confirmed patients across 14 regions in southern and central Sweden.

Almost three quarters of patients are children younger than 10 years of age and four are older than 70.

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Reports from local authorities have not been fully compiled yet but based on preliminary information officials believe more than 100 people have fallen sick.

It is mostly local outbreaks at workplaces where people have eaten shrimp sandwiches or a popular product in Scandinavia called “smörgåstårta.” This food, also called a sandwich cake, looks like a cake but instead of sponge uses bread and often includes cheese, vegetables, cold meats and fish.

Peeled shrimps in brine from the implicated batch were mostly distributed within one region which was named by local media as Varnamo in Jönköping County in southern Sweden.

Outbreak investigation
The outbreak began on the last weekend of February. The implicated batch was withdrawn from the market on March 1 when the distributing company received information about the first illnesses.

Mats Lindblad, from Livsmedelsverket (the Swedish Food Agency), said the link was made by patient interviews with product testing results pending.

“So far it’s based on interviews with cases and backwards and forward tracing of food. Results from product testing are still pending, but samples of shrimps from the implicated batch have been sent to the Swedish Food Agency for microbiological analysis of norovirus,” he said.

“The product has only been sold to food business operators producing shrimp sandwiches or smörgåstårta. Therefore, no public recall has been deemed necessary.”

Lindblad said because of the limited distribution and withdrawal measures more illnesses are not expected.

The most common symptoms of norovirus are diarrhea, vomiting, nausea and stomach pain. Other symptoms may include low-grade fever, headache, chills, muscle aches and a sense of tiredness.

A person usually develops symptoms 12 to 48 hours after being exposed to norovirus. Most people with illness get better within one to three days. People who are ill should drink plenty of liquids to replace lost body fluids and prevent dehydration.

Norovirus is transmitted by having contaminated food or water or from person to person through contact with the skin, objects or inhaling airborne particles.

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The document compiles reported foodborne illness for 2008 to 2018. There were more than 4,000 events of suspected or confirmed disease with 30,964 illnesses.

During the period, 194 of the country’s 290 municipalities reported results from investigated incidents of foodborne illness to the Swedish Food Agency (Livsmedelsverket). The number of reporting municipalities per year has increased since the previous summary covering 2003 to 2007.

In 80 percent of reports, the disease-causing agent was unknown. Bacteria or toxins were identified in 13 percent of the reports, while viruses were implicated in 7 percent of them. Only a few concerned parasites, marine biotoxins or mycotoxins. Results will be used as a basis for risk assessment and to form priorities to reduce foodborne illness in the country.

Lack of reporting
The report also found only about one in 100 people report suspected food poisoning to the local food control agency. If more did, authorities would be able to trace the cause easier and prevent more people from getting sick.

It showed reporting has increased, but most cases are still unlikely to be brought to the attention of authorities. If agencies quickly become aware of a patient, they can analyze the suspected food and stool samples from the person who is ill.

“Many people probably do not know that you should notify the food control authority in their municipality when you suspect that you have food poisoning. If more people did, the authorities would be better able to track and stop infection and also put in place measures to prevent food poisoning,” said Jonas Toljander, risk assessor at Livsmedelsverket.

Broiler meat was the food category behind the most reported cases with 53 outbreaks and 5,357 cases and most can be attributed to a national outbreak of campylobacteriosis in 2016 to 2017. Mixed foods, such as pizza, kebabs and sandwiches accounted for almost as many cases. Buffet food also made up 98 reports and 1,397 cases while vegetables were linked to 50 reports and 1,265 cases.

Large norovirus and Campylobacter outbreaks
The majority of reported food poisoning cases were caused by norovirus. Mixed foods were most commonly identified as the source in outbreaks. Spread was largely caused by infected individuals handling food during preparation. Food from an open buffet, oysters from other EU countries, and frozen imported raspberries were also frequent sources of contamination.

The largest norovirus outbreak sickened 681 people and was one of 35 outbreaks to affect more than 100 people. There are signs norovirus spread less in Sweden in 2020 than before, as many people have washed their hands better and more because of the coronavirus pandemic.

Campylobacter was the second top cause of foodborne illness with 83 reports and 5,589 cases. The 2016 and 2017 outbreak from chicken affected 5,150 people. In addition to chicken, other meat products, mixed foods, and items such as unpasteurized milk, were implicated in several reports as sources of infection.

Salmonella caused 99 reports and 1,472 cases. Various vegetables were identified as the source of infection for slightly more cases than meat and dairy products. A total of 24 serotypes were found. Salmonella Typhimurium, including monophasic Typhimurium, was mainly reported and also affected the most people. Salmonella Enteritidis was the second most common serotype.

Histamine was responsible for 126 reports, Bacillus cereus for 38, Shiga toxin-producing E. coli for 36, Listeria for 16, Clostridium perfringens for 15 and Shigella for 13. A total of 11 deaths linked to food poisoning were reported in 2008 to 2018 with six caused by Listeria and one due to STEC.

In 223 reports country of origin of the food vehicle was indicated and in 112 it was from abroad. Of these, 68 were reports on food imported from outside the EU.

Most reported cases are caused by improper handling of food by caterers and restaurants. Lack of hygiene skills is the main contributing factor to food poisoning.

Presence of pathogens in food points to deficiencies in primary production or slaughter. Lack of temperature control can lead to bacterial growth and formation of bacterial toxins in food. Apart from risk-mitigating measures in primary production, steps such as improved hygiene and keeping food at the proper temperature could prevent most food poisonings, according to the report.

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