Efficacy of nisin against Staphylococcus aureus in experimentally contaminated sucuk, a Turkish-type fermented sausage.

Abstract

Sucuk is a fermented sausage widely consumed in Turkey. The ability of different concentrations of nisin to inhibit Staphylococcus aureus in artificially contaminated sucuk was examined. Sucuk dough was prepared, inoculated with S. aureus ATCC 25923 at a level of 10(6) CFU/g, and then divided into six equal portions to which different concentrations of nisin (0, 25, 50, 100, 150, 200 mimcrog/g) were added. Microbiological (S. aureus, total mesophilic aerobic bacteria, and lactic acid bacteria) and physicochemical (pH, water activity, and moisture) analyses were conducted initially and after 1, 3, 5, 10, 15, 20, 25, 30, 35, and 45 days. S. aureus populations decreased to below detectable limits in sucuk containing 200 or 150 microg of nisin per g after 30 and 35 days of storage, respectively, whereas S. aureus populations in 45-day-old sucuk containing 0, 25, 50, and 100 microg of nisin per g were 5.36, 5.68, 4.10, and 3.54 log CFU/g, respectively. Hence, the addition of nisin at 150 microg/g or greater to sucuk dough can be used to prevent the growth of S. aureus in sucuk during fermentation and subsequent storage.