Norway – Analyzes of Pathogenic Escherichia coli in bacon sausages 2022


On behalf of the Norwegian Food Safety Authority, the Norwegian Veterinary Institute has examined 137 Norwegian bacon sausages for pathogenic E. coli bacteria (STEC). There was a discovery of such bacteria, but this type does not usually cause serious illness in humans. Although the sample was small, the conclusion is that the prevalence of STEC in Norwegian bacon sausages is low.


What we investigated: 137 Norwegian bacon sausages
Period: The samples were obtained in 2020 and analyzed in 2021
What we were looking for: E. coli and pathogenic STEC variants
What we found: A positive E. coli sample. This was not the type that usually causes serious illness in people, ie good results.
Who carried out the assignment: Veterinary Institute
Escherichia coli is present in the gastro intestinal tract of humans and warm-blooded animals, and are usually harmless. However, some groups of E.coli may cause infections in humans. Shiga toxin-producing E. coli (STEC) is one of the groups of pathogenic E. coli. Ruminants, in particular cattle, are assumed to be the main reservoir for STEC.
The results from previous surveys of cattle and sheep in Norway for the occurrence of STEC of the serogroups most often associated with infection, have indicated a low occurrence. Similar results were observed in a survey of minced meat from cattle, on the Norwegian market. The Norwegian Food Safety Authority commissioned a survey of STEC in domestically produced fermented sausages. The samples were collected in 2020 with subsequent analysis in 2021.
A total of 137 samples of domestically produced fermented sausage were collected and analysed. Enriched samples were examined for the presence of the genetic markers stx1, stx2 and eae. Attempts of isolation were carried out from samples that were positive for one or more of the virulence markers. Isolates identified as STEC were further characterized using whole genome sequencing.
STEC was isolated from only one sample, and the isolate was characterized as STEC O76:H19 harbouring stx1c, but did not carry eae. In the primary screening of enriched samples, only a few samples were positive for the virulence markers. The results from this study indicates that the occurrence of STEC in
Norwegian fermented sausages is low.
Although STEC was isolated, none of the serogroups associated with severe infections were isolated. It must be taken into account that a low number of samples were analysed. Since this type of products has not been analysed previously, the present survey provides knowledge for the industry, authorities and knowledge institutions. It is important to carry out similar surveys regularly to generate updated Norwegian data.

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