Toxoplasma gondii is at the top of a risk ranking report of 20 pathogens in Norway.

It was followed by Campylobacter, Echinococcus multilocularis, enterohaemorrhagic E. coli (EHEC), Listeria monocytogenes, and non-typhoidal Salmonella, according to the Norwegian Scientific Committee for Food and Environment (VKM).

The Norwegian Food Safety Authority (Mattilsynet) commissioned the report, which will be used for risk-based prioritization of programs for monitoring and controlling pathogens in food and water.

Risk ranking was based on the number of water and foodborne illnesses, severity of acute and chronic disease, fraction of chronic illness, fatality rate, and the probability for future increased disease burden. Six criteria related to public health were weighted to calculate an overall risk score for each pathogen.

VKM looked at data from national surveillance and monitoring programs, prevalence surveys, outbreak investigations, and research, including epidemiological studies. When there was a lack of Norwegian data, international reports were used.

The bottom five pathogens were Clostridium Botulinum, Staphylococcus aureus, Clostridium perfringens, Bacillus cereus and Anisakidae.

If number of foodborne illnesses was the most important criterion, the highest ranked pathogens become norovirus and Campylobacter. When morbidity severity has maximal importance, the order is Toxoplasma, E. multilocularis, EHEC, Clostridium botulinum and Listeria.

Source attribution findings
VKM also identified which foods the pathogens are commonly found in, the importance of food as a source of infection, and the main risk factors.

Fresh vegetables were one of the most important food sources for 12 of the 20 infectious agents, drinking water was associated with eight, and five were linked to raw milk products.

The main food vehicles of Toxoplasma gondii were undercooked meat from sheep, pigs and cattle and unwashed fresh produce. For E. multilocularis it was eating unwashed raw vegetables, herbs, fruits or berries contaminated with parasite eggs or drinking contaminated water.

Drinking water and poultry are the main vehicles for Campylobacter as well as consumption of raw, unpasteurized milk and dairy products. For Salmonella, it was various imported foods of animal or vegetable origin and foreign travel.

Undercooked meat from sheep and cattle, fresh produce and unpasteurized milk products were the top vehicles for EHEC while for Listeria the list included cold cuts, soft cheeses, fermented fish (rakfisk) and unpasteurized milk products.

Taran Skjerdal, scientific leader of the team, said there was great variation in which foods were the source of each pathogen.

“The results may change over time as new data become available from monitoring and research on pathogens and the diseases they cause. The systematic and transparent process described in this report will probably be most useful if it is repeated and updated regularly with new information,” she said.

The Norwegian Food Safety Authority has also announced it will prioritize inspections of sites that handle meat from EU and European Economic Area countries after several findings of Salmonella in products from Germany earlier this year. A Salmonella Enteritidis outbreak from beef imported from Germany sickened at least 22 people earlier this year.

The agency will require the company to verify that consignments of traded beef and pork meet the Salmonella-relevant conditions in the Animal Hygiene Regulations. This can be done by through documentation or increased sampling.