Inhibition of Listeria monocytogenes in cold smoked salmon by addition of sakacin P and/or liveLactobacillus sakei cultures

Abstract

Listeria monocytogenes is the causative agent of food-related listeriosis. It has the ability to grow in vacuum-packaged food at chiller temperatures and is relatively tolerant to salt and low pH, thus it is difficult to control its growth in food.Listeria monocytogenes was added to vacuum-packed cold smoked salmon together with known concentrations of the bacteriocin sakacin P or nisin and/or one of two isogenic strains of the lactic acid bacteriaLactobacillus sakei . The vacuum-packaged salmon samples were incubated at 10°C for 4 weeks. Of the isogenic L. sakei strains, one produced sakacin P and the other did not. Both sakacin P and nisin had an initial inhibiting effect on growth of L. monocytogenes. Addition of the sakacin P-producing or the non-producing L. sakei had a bacteriostatic effect on L. monocytogenes during the complete storage period. When the sakacin P-producing L. sakei culture was added to vacuum-packed cold smoked salmon together with sakacin P, a bacteriocidal effect on L. monocytogenes was observed.