The effect of nisin and bovine lactoferrin on the microbiological quality of Turkish-style meatball (Tekirdag kofte)

Abstract

Tekirdag kofte, a Turkish-style meatball, is one of the most popular ground meat products in Turkey. The aim of this study was to evaluate the effect of different nisin and lactoferrin (Lf) concentrations and their combinations on the microbiological quality of Turkish-style meatball (Tekirdag kofte). For this purpose, the meatball dough was divided into six equal groups, and each of the groups was treated separately with different nisin and/or Lf concentrations (0, 100 and 200 mu g/g). Analyses were performed on each meatball group at 0, 1, 3, 5, 7, 10 and 12 days for microbiological parameters (total mesophilic aerobic bacteria, lactic acid bacteria, coliforms, Escherichia coli, total staphylococcae, Staphylococcus aureus, total psychrophilic bacteria, Pseudomonas spp., sulfite-reducing anaerobic bacteria, and yeast and mold) and physicochemical analyses (pH, water activity and moisture). Treatment with Lf alone and its combination with nisin significantly reduced (P < 0.05) the total aerobic bacteria, coliform, E. coli, total psychrophilic bacteria, Pseudomonas spp., and yeast and mold counts in meatballs. The largest reduction in these counts occurred on the meatballs treated with a mixture of Lf (200 mu g/g) and nisin (100 mu g/g). This combination prolonged the refrigerated shelf life of naturally contaminated Turkish-style meatballs to 10 days compared to 3 days for nontreated control.