Almost 90 people are part of an outbreak in Denmark from Campylobacter after eating chicken meat from one slaughterhouse.

Statens Serum Institut (SSI), the Danish Veterinary and Food Administration (Fødevarestyrelsen) and DTU Food – National Food Institute investigated the Campylobacter jejuni outbreak.

As part of a project this past year involving the Clinical Microbiology Department (KMA) in Aalborg, Danish Veterinary and Food Administration and SSI; Campylobacter isolates from patients diagnosed in Aalborg beginning in March 2019 were collected, sent to SSI and whole genome sequenced.

Campylobacter isolates are not routinely submitted and sequenced so the outbreak has likely been detected because of the project, according to officials. Campylobacter jejuni sequence type 122 was identified in patients by whole genome sequencing.

HKScan’s response
This type was also found in chicken meat from one slaughterhouse belonging to HKScan in Vinderup, a town in Northwestern Jutland. Products from this site are sold at all the major Danish retail chains. It was previously revealed that the Danish Veterinary and Food Administration (DVFA) sent officials to help the company track and eliminate the source of infection. Vinderup is HKScan’s main site in Denmark and supplies meat to other countries.

A HKScan spokeswoman said the firm has worked in co-operation with authorities and jointly agreed on action plans which are being followed up to monitor progress.

“The bacteria has been traced back to one single farm. All products from this farm have been isolated and risk assessed by DVFA. Immediately after HKScan was informed by the authorities of the outbreak, all meat from this farm has been frozen and not released for sale until food authorities have risk assessed the products,” she told Food Safety News.

“At the Vinderup site we have intensified the cleaning and the disinfection of the slaughtering, packaging areas and transport equipment to prevent the bacteria from spreading. Chickens from the farmer have been contained and slaughtered as the last ones before cleaning. The areas have afterwards been tested extensively for Campylobacter to ensure that areas are completely clean and no cross contamination is possible.”

The spokeswoman said HKScan took the outbreak seriously and is investing in modern live bird handling system to further secure food safety.

“HKScan is actively participating to the agreed national Campylobacter plan in Denmark together with the whole industry. We are following closely all agreed steps in the plan. In addition to the national Campylobacter plan HKScan initiated a project to further reduce Campylobacter at a farm level in early 2019 with veterinarians, inspection and audit action plans.”

The company provides information on kitchen hygiene with all products. This includes keeping raw chicken products and packaging materials separated from other food. Cleaning kitchen utilities thoroughly and washing hands after handling chicken products and always preparing poultry until meat juice is clear and the core temperature is 75 degrees C (167 degrees F).

Between February 2019 and Jan. 9, 2020, 88 patients with the same type of Campylobacter have been identified. Among the sick were 35 women and 53 men aged 2 to 91 years old. The outbreak appears to be declining with fewer infections toward the end of 2019.

Steen Ethelberg, from SSI, said the project ran in 2019 but will be continued in moderated form in 2020. Human isolates from the Aalborg clinical lab will be sequenced in real time this year.

“We will keep following it but it is primarily now in the hands of the Danish Veterinary and Food Administration. It has worked with the industry to contain and stop the outbreak. It is not quite clear if it is over but the number of new cases went down,” he told Food Safety News.

Greater understanding of outbreak
Ethelberg said a lot has been learned from sequencing Campylobacter isolates but project partners haven’t yet had a chance to meet, discuss and digest all the data. A scientific publication is planned on the results.

“We’ve have reconfirmation of the fact that many hitherto unknown clusters and outbreaks are uncovered with sequencing and that chicken products on the market can be associated with a part of these. Also we’ve uncovered a single huge outbreak. This we would likely not have understood as well as we do, without the sequencing.”

Campylobacter is the main cause of bacterial intestinal infections in Denmark. In 2019, 5,300 cases were recorded which is up from the 4,500 infections registered in 2018.

“Campylobacter is a big concern. The numbers tend to go up or down with a few hundred cases from year to year, which is probably natural variation. In 2019, we believe a part of the explanation for the increase is the large outbreak,” said Ethelberg.

“The cases we count is based on the number of isolates sequenced, so in reality there could be several fold more cases if we assume that the outbreak affected the entire country. And again, this we would not have understood without the sequencing.”