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

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 contr ol its growth in food. Listeria monocytogenes was added to vacuum-packed cold smoked salmon togeth er with known concentrations of the bacteriocin sakacin P or nisin and/or o ne of two isogenic strains of the lactic acid bacteria Lactobacillus sakei. The vacuum-packaged salmon samples were incubated at 10 degreesC for 4 wee ks. 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 growt h of L. monocytogenes. Addition of the sakacin P-producing or the non-produ cing L. sakei had a bacteriostatic effect on L. monocytogenes during the co mplete storage period. When the sakacin P-producing L. sakei culture was ad ded to vacuum-packed cold smoked salmon together with sakacin P a bacterioc idal effect on L. monocytogenes was observed. (C) 2001 Academic Press.