Bacteriocin-like substances of Lactobacillus curvatus P99: characterization and application in biodegradable films for control of Listeria monocytogenes in cheese

The aim of this study was to evaluate the effectiveness of a biodegradable film, with antimicrobial metabolites produced by Lactobacillus curvatus P99 incorporated, targeting the control of Listeria monocytogenes in sliced Prato cheese. Tests were performed to evaluate the spectrum of action of cell-free supernatant (CFS) of P99 against different microorganisms, as well as to detect the minimum inhibitory (MIC) and bactericidal (MBC) concentrations against L. monocytogenes Scott A. The detection of genes that encode for the production of bacteriocins and evaluation of their expression were performed. Antimicrobial films were prepared, followed by in vitro and in situ analysis. The MIC and MBC of CFS against L monocytogenes Scott A was 15.6 mu L/mL and 62.5 mu L/mL, respectively. Lactobacillus curvatus P99 presented two genes coding for the bacteriocins, which were expressed. Films with added MBC showed activity against different indicator microorganisms and were able to control L monocytogenes Scott A when used in sliced Prato cheese. (C) 2016 Elsevier Ltd. All rights reserved.