Campylobacter bacteria can be found in foods, such as poultry meat and unpasteurized milk, as well as contaminated drinking water. Studies have shown that chicken meat is the largest known source of human infection with campylobacter, but there are a number of other significant sources. In 2016 and 2017, the Danish Veterinary and Food Administration, in collaboration with the Technical University of Denmark (DTU) and Statens Serum Institut (SSI), investigated different sources for human infection in Denmark. The results showed that chicken meat is the largest single source of campylobacteriosis in people infected in Denmark. Other sources of infection are cattle (both direct contact with cattle and drinking raw milk). For children in particular, contact with dogs and fresh strawberries may be a source of infection.
Campylobacter is common in the intestines of many animals, including pigs, cattle, chickens, and dogs. The bacterium can be spread from the animals' intestines via manure or faeces e.g. during slaughter.
A few drops of meat juice with campylobacter may be enough
Campylobacter is a problem in food because only a few drops of meat juice from raw meat may be enough to make you sick.
Campylobacter cannot grow in food, and freezing can reduce the number of campylobacter and minimize the risk of disease.
Most people contract campylobacter in the summer. This is partly due to more people travelling abroad during summer. But it is also due to the fact that campylobacter is more prevalent in broilers during summer, and also more prevalent in chicken meat at that time of year. To avoid getting sick from campylobacter, you should pay attention to good kitchen hygiene, especially when handling raw meat.
Statens Serum Institut (SSI) registers more than 5,000 human cases of campylobacteriosis every year. The National Food Institute, Technical University of Denmark, estimates the real number to be about 12 times higher, partly due to many people not going to the physician. Anyone may contract campylobacteriosis, but it is more prevalent among young people compared to other age groups.
Since 2019, it has been possible to detect and solve more campylobacter-outbreaks. SSI and the Danish Veterinary and Food Administration examine a proportion of the bacteria-isolates from food sources and human patients by whole genome sequencing. The results are compared and findings in food may be linked to findings from human patients.
See the graph for the number of people sick with campylobacter here on Statens Serum Institut's website (in Danish)
Read more about campylobacter here on Statens Serum Institut's website
If you have campylobacteriosis, you may experience stomach ache and diarrhoea. Other symptoms of illness include nausea and fever. Symptoms usually begin 2-10 days after eating food contaminated with the bacteria. You will typically recover within a few days without medical attention. It is important to drink plenty of water or juice if you vomit or have diarrhoea to avoid dehydration.
If the illness becomes severe or lasts for a long time, you should see a doctor. If the illness is suspected to be caused by a particular food, the doctor can report it to the Medical Officer of Health, who has an overview of whether several people have become ill from the same food, e.g. in the same city or the same municipality. In addition to calling the doctor, you or the doctor can contact the Danish Veterinary and Food Administration, who may help clarify the cause of the disease.
In Denmark, authorities, industry organisations and research institutions are working together to prevent and control campylobacter in food, to reduce the number of human cases.
Campylobacter is far from a unique Danish problem, and both Denmark and a large number of other countries are doing a lot of work to combat campylobacter.
Since 2003, Denmark has had a strategy to combat campylobacter in food, and in 2008 the first action plan was ready. The strategy and action plan focused on reducing the occurrence of campylobacter in the production of broilers and chicken meat, because chicken meat is the largest known source of human campylobacteriosis. Studies have since shown that there are other sources of infection than chicken meat. Therefore, the latest action plans contain efforts to gain more knowledge on these sources of infection. Among other things, a source attribution study has been carried out by the Technical University of Denmark (DTU). This shows that chicken meat is still the main source of human campylobacteriosis.
The action plan for 2022-2026 builds on and continues the initiatives in the previous plans, with efforts to reduce campylobacter in the herds and at the slaughterhouses. The measures agreed by the industry and the authorities to combat campylobacter in primary production (broiler producers) and in the slaughterhouses (fresh meat) have been continued. The action plan also continues coordinated surveillance of the main food sources, i.e. mainly poultry meat, as well as of infected people. As a result, it is possible to detect and stop disease outbreaks.
Statens Serum Institut (SSI) estimates that approximately one in three people contract campylobacter while travelling abroad. Therefore, efforts are also being made to inform consumers about how they can avoid being infected while travelling abroad. In addition, efforts are being made to inform about the safe handling of fresh chicken meat in the kitchen.
The overall goal of the action plan is to reduce the number of people who become ill from campylobacter. Individual targets have been set to reduce the prevalence of campylobacter in the chicken meat at the individual slaughterhouses. It is a goal to maintain the low level of infected chicken flocks.
See the action plan for campylobacter 2022-2026 (in Danish)
See the action plan for campylobacter in broilers, food and the surrounding environment 2018-2021 (in Danish)
The National Food Institute at the Technical University of Denmark is responsible for risk assessment of campylobacter in Denmark. In 1998, the National Food Institute prepared a risk profile for campylobacter and in 2001 a risk assessment of campylobacter in broiler chickens in Denmark. The risk profile and risk assessment have since formed the scientific basis for the Danish Veterinary and Food Administration's handling of campylobacter in food. Among other things, it shows that there is a significantly lower risk of eating chicken meat that has been frozen.
Since then, studies and research projects have been carried out to clarify how action can be taken both in broiler flocks, at the slaughterhouse and during cutting and packing, as well as at the retail and consumer level.
In 2016-2017, the National Food Institute, Technical University of Denmark, prepared a new source attribution study for campylobacter. It showed that chicken meat is still the largest source of infection with campylobacter in Denmark, and that there are other major sources, e.g. cattle. The source attribution study, together with a case-control study from Statens Serum Institut, have formed the basis for a large part of the new initiatives in the action plan against campylobacter.
See the report on campylobacter – possible spread from primary production (in Danish)
See the source attribution from DTU: Source attribution of Campylobacter infections in Denmark
Find information about the case-control study from the SSI here: Large study finds possible sources of infection for Campylobacter in Danes (in Danish)
Monitoring is part of the action plan against campylobacter. The Danish Veterinary and Food Administration monitors campylobacter in chicken meat at the slaughterhouse and takes samples of the fresh meat at the retail level and at wholesale storage facilities. The slaughterhouses monitor each broiler flock for campylobacter by taking samples of intestinal contents from chickens at slaughter. Slaughterhouses also monitor the slaughter process to limit spread during the slaughter process.
Since 2019, the Danish Veterinary and Food Administration has examined samples from various sources for campylobacter, where a proportion of the bacteria are whole-genome sequenced and compared with campylobacter from patients with campylobacter. The project is carried out in collaboration with Statens Serum Institut. This has uncovered several outbreaks of disease, some of which have been linked to Danish-produced chicken meat. So far, it is primarily campylobacter from chicken meat that has been included in the project, and to a lesser extent campylobacter from cattle.