The number of foodborne outbreaks in the Netherlands passed 800 in 2021, according to the National Institute for Public Health and the Environment (RIVM).

A total of 838 outbreaks, affecting 3,517 people, were reported in 2021. This is an increase compared with 559 outbreaks in 2020 affecting 1,907 people and is also up from 735 outbreaks in 2018 and 756 in 2019.

Salmonella and Campylobacter were still responsible for most outbreaks and illnesses this past year. Norovirus was reported far less than in previous years for the second year in a row.

Figures come from the Netherlands Food and Consumer Product Safety Authority (NVWA) and Municipal Health Service (GGD).

Pathogen unknown for most outbreaks
Based on NVWA statistics, most outbreaks involved two to four and five to nine patients. Twenty or more sick people were registered in 13 outbreaks, with 71 and 79 patients in two norovirus incidents. More than 400 people were affected in one outbreak caused by an unknown pathogen. From GGD figures, in 28 outbreaks, four people died from listeriosis.

A pathogen was found in patients, food or environmental samples for only 28 of the 838 outbreaks. Experts said the percentage of outbreaks where a pathogen was identified continues to decrease but the reason for this is uncertain.

Salmonella caused at least 11 outbreaks in 2021 with 205 cases and five Campylobacter outbreaks were reported with 11 sick.

There were two outbreaks from Listeria monocytogenes and Hepatitis A that affected nine and 24 people, respectively. STEC and Yersinia enterocolitica were both linked to one outbreak with 12 and six related infections.

People are cooking at home more often than before the coronavirus pandemic and more outbreaks have been reported in domestic settings than in previous years. In 2020 and 2021, the private setting was the preparation site in an average of 10 to 15 percent of outbreaks. In comparison, from 2006 to 2019, this setting was linked to an average of 6.6 percent of outbreaks.

Solved incidents
A pathogen was detected in food in three cases and environmental samples in seven outbreaks.

Listeria monocytogenes was found in monitoring samples from production sites that linked, via WGS, to a cluster of patients. It was found on smoked salmon in one outbreak and on smoked fish in another.

The Netherlands was also affected by an international Salmonella Braenderup outbreak caused by Galia melons from Honduras. The country recorded 34 cases.

In two of 18 outbreaks where the pathogen was only found in the patient, there was a strong link to a food source. The E. coli O157 outbreak in the Northern Netherlands was linked to carpaccio – an appetizer with raw meat or fish. Filet Americain, a type of raw beef spread, was behind a Campylobacter outbreak with three cases.

In the largest outbreak affecting 402 people in October, a group of 900 employees received a packed lunch from a catering company as part of a training session in 31 locations. The likely source was a vegan chicken sandwich. Fecal samples were negative for rotavirus, adenovirus, norovirus, sapovirus, STEC, Campylobacter, Salmonella and Shigella but no toxin testing was performed.

An inspection at the catering company, during which food and environmental samples were taken, found no shortcomings. Leftover food samples were also negative for pathogens but tests for Bacillus cereus and Clostridium perfringens were not included because the analytical methods were not available at the Wageningen Food Safety Research lab that performs sample analysis for the NVWA.

An outbreak of Salmonella Enteritidis has sickened 26 people since 2018 and Germany also reported two infections. Patient isolates matched an environmental sample from a farm in 2019. Measures had been imposed on the producer so it could only sell eggs for further processing and not to retailers due to the detection of Salmonella in barns but these had been lifted a few months before the link was made because of negative results. The measures were reinstated until the company demonstrated the problem had been managed.

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