Salmonella occurring at low levels in the Finnish food chain

May 15/2019

Finnish poultry causes only a very small percentage of all salmonella infections in Finland whereas Finnish beef may cause the highest percentage of salmonella infections. Imported meat, on the other hand, might cause even slightly more salmonella infections than meat produced in Finland in total, even though the consumption of imported meat covers only a small percentage of the consumption of Finnish meat in Finland. This and other things were discovered by using the statistical model developed in the Risk Assessment Unit of the Finnish Food Authority. The model can be used to evaluate the roles of various food categories in causing human salmonella infections. The model makes use of information from a period of several years, making it more suitable than earlier statistical models for countries like Finland, where cases of salmonella are relatively few in total.

The potential origins of food-based salmonella infections in consumers were assessed based on information from between 2008 and 2015. During this time, the annual total number of infections was reduced by half from about 3,000.  The number of infections acquired from Finland varied from approximately 300 to 400 cases.

The studied food categories included chicken and turkey meat, beef and pork. Finnish and imported meat were examined as separate categories.

“Based on the research material, about two thirds of annual human salmonella infections of Finnish origin represent subtypes of salmonella that were also identified in the studied food categories. As evaluated by using the model, three subtypes of salmonella with the relatively highest risk levels were Enteritidis 8, Newport and Enteritidis 1b. Turkey meat imported to Finland showed the relatively highest value as a source of infection”, says Researcher Antti Mikkelä from the Finnish Food Authority.

The method compares the subtypes of salmonella diagnosed in humans (serotypes and phage types) to types observed in foodstuffs and production animals while also taking into account the occurrence of salmonella in foodstuffs and their volume of consumption. In addition, the method is used to describe and evaluate the differences between risk levels of various subtypes of salmonella and food categories. Finally,  the overall information from the various sections of the model is used when connecting salmonella infection percentages to various sources of infection.

“The major challenge ahead is extending the model so that more accurate laboratory methods, such as genotyping results, can also be used in connecting infections”, says Research Professor, Docent Jukka Ranta from the Finnish Food Authority.

The development of the current model is continuation for the Health risks of food-borne bacterial infections and tracing the Finnish cases project funded by the Academy of Finland and the Ministry of Agriculture and Forestry, carried out from 2008 to 2010.

Read more from the research article:
Mikkelä, A., Ranta, J., Tuominen, P.
A Modular Bayesian Salmonella Source Attribution Model for Sparse Data. Risk Analysis 2019. 

Further information:
Researcher, Antti Mikkelä, Risk Assessment Unit, tel. +358 400 211 624
Research Professor, Docent Jukka Ranta, Risk Assessment Unit, tel. +358 40 489 3374
Head of Unit, Docent Pirkko Tuominen, Risk Assessment Unit, tel. +358 400 211 624