The number of foodborne outbreaks declined in the Netherlands this past year with officials citing COVID-19 related measures as the main reason.

In 2020, there were 559 outbreaks with 1,907 patients reported. This is less than 756 outbreaks affecting 2,805 people in 2018 and 735 outbreaks sickening 3,058 in 2019.

Norovirus, Salmonella and Campylobacter are still the cause of most outbreaks, but at a much lower level than previous years. Eight Campylobacter outbreaks were recorded, five for Salmonella and three for norovirus. There were three Listeria outbreaks and one each for Bacillus cereus, Ciguatera and Shigella. The agent was unknown for 537 outbreaks.

The decrease is primarily because of the coronavirus pandemic and measures taken to reduce its spread, such as handwashing, increased hygiene, temporary closure of catering firms and reduced contact because of lockdowns, according to the report.

Figures come from the Netherlands Food and Consumer Product Safety Authority (NVWA) and the municipal public health services (GGDs) and were published by the National Institute for Public Health and the Environment (RIVM).

Listeria outbreak traced to cheese
This past year, 27 hospital admissions were reported, of which 23 were because of Listeria infections and four because of Salmonella. Five people across three outbreaks also died of listeriosis compared to an overall number of 53 hospitalizations and six deaths in 2019.

The largest outbreak was because of norovirus with 63 sick, followed by 56 patients in a Salmonella outbreak and 43 patients in an incident with an unknown agent.

Overall, Salmonella outbreaks affected 87 people, norovirus events had 85 patients, Campylobacter was responsible for 26 patients and Listeria 24 patients. The Bacillus cereus outbreak had three patients, a Ciguatera outbreak involved five people and four were ill in the Shigella outbreak.

In two of the 22 outbreaks in which a germ was detected, it involved a pathogen in food. Bacillus cereus was found in a frozen tuna burger and signs of Ciguatoxin were detected in red snapper fish.

Listeria monocytogenes was found three times in samples that, thanks to whole genome sequencing, was linked to patients. In all three, contamination occurred during production or processing and was linked to fish on two occasions and once to soft cheese.

In the Netherlands, the cheese outbreak involved six people from June 2019 to December 2020 and 18 more patients from three other countries between June 2019 and January 2021. Goat’s cheese was recalled in late 2020 after environmental Listeria contamination. The company took steps to improve hygiene and control the pathogen with no sick people reported since.

Salmonella, Campylobacter and Ciguatera outbreaks
In 17 outbreaks, a pathogen was only found in the patient. A Salmonella Enteritidis outbreak with 56 patients in August 2020 was linked to Turkish pizza from one catering business. The incident initially affected an institution for the mentally and physically disabled but more cases have been identified in the community since July by WGS.

No Salmonella was found at the outlet and which ingredient was contaminated is unknown.  Salmonella was found at the raw material producer for the chicken doner but it was a different type.

Preparation sites of suspected food were mainly restaurants and cafeterias. In half of the outbreaks the food under suspicion was eaten at home and in just under half it was consumed at the same location as it was prepared.

In July 2020, two people in the same family fell sick from Campylobacter after drinking unpasteurized milk bought from a farm but no Campylobacter was found in milk samples at the site. Campylobacter jejuni was detected in the stool of one of the patients. Raw milk offered for sale must bear a statement that it is to be boiled before consumption. It is not known whether the patients boiled the milk before drinking it.

In May, a group of five people ate fish and fell ill with Ciguatera poisoning a few hours later. The red snapper, from India, was bought at a shop and prepared at home. Leftovers from the freezer of one patient were tested and suspected to be above internationally established limits.

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