Is Listeria innocua 2030c, a tetracycline-resistant strain, a suitable marker for replacing L. monocytogenes in challenge studies with cold-smoked fish?

The suitability of Listeria innocua 2030c, a tetracycline-resistant strain, to be used as an indicator for replacing Listeria monocytogenes in challenge studies with cold-smoked fish was ascertained. L. innocua 2030c was compared to serovars 4b and 1/2c of L. monocytogenes, the major types isolated from Portuguese cold-smoked fish products. Growth curves at 30°C, growth/survival patterns at 30°C under exposure to different times and concentrations of ozone and sensitivity to Carnobacterium divergens V41 and C. piscicola V1 and their bacteriocins V41 and V1, were determined. No important differences between L. innocua 2030c and L. monocytogenes 4b and 1/2c were found, therefore L. innocua 2030c can be considered a suitable indicator for replacing those L. monocytogenes strains in challenge studies.