Turkish fermented sausage (sucuk) is a traditional, well-known meat product in Turkey. The aim of this study was to evaluate the effect of different nisin concentrations on Listeria monocytogenes in experimentally contaminated sucuk. Analyses were performed on at 0, 1, 3, 5, 7, 10, 15, 20, 25 and 30 days for L. monocytogenes and other microbiological parameters (Total mesophilic aerobic bacteria and lactic acid bacteria) and physico-chemical parameters (pH, a(w) and moisture content). The sucuk dough was contaminated with L. monocytogenes ATCC 7644 at a concentration of 10(6) cfu/g, and the dough was divided into six equal groups. Each group was treated separately with different nisin concentrations (0, 5, 10, 25, 50 and 100 mu g/g). No L. inonocytogenes surviving cells were detected in groups which contained 100 mu g/g and 50 mu g/g nisin at day 20 and 25, respectively (p < 0.001). In conclusion, the inhibition of L. monocytogenes in sucuk increases with the increasing concentrations of nisin. (c) 2006 Elsevier Ltd. All rights reserved.