A team of researchers in the USA have discovered that the foodborne pathogen Listeria monocytogenes uses different metabolic pathways to grow on refrigerated smoked salmon from those it uses when growing in laboratory culture media.
The team, led by Dr Teresa Bergholz, assistant professor in the Department of Veterinary and Microbiological Sciences at North Dakota State University, grew Listeria on cold-smoked salmon and in a broth medium modified to have the same pH and salt concentration as the fish and then used RNA-sequencing to compare the genetics of metabolism in each case.
They found that the bacterium up-regulated genes to allow it to use two compounds found in cell membranes – ethanolamine and propanediol – as sources of energy when growing on the smoked salmon.
It is hoped that the findings will help to formulate control strategies and improve risk assessments for Listeria on ready-to-eat foods like smoked fish.
The research is published in the journal Applied and Environmental Microbiology and an abstract of the report can be found here.