Inhibition of individual and combination of cell free supernatants of phenyllactic acid, pediocin- and nisin-producing lactic acid bacteria against food pathogens and bread spoilage molds

Abstract

Consumer demand has led to an increase in the use of natural antimicrobials for baked good preservation. In this study, the cell-free culture supernatants of three antagonistic bacterial strains were tested, and their individual and combined antimicrobial effects on Escherichia coli, Bacillus cereus, Aspergillus neoniger, and Penicillium roqueforti were examined. The mixture of phenyllactic acid and pediocin with ethylenediaminetetraacetic acid (EDTA) exhibited a strong inhibitory effect on E. coli growth (RIA 85%). Nisin mixed with phenyllactic acid or pediocin with EDTA exhibited a strong inhibitory effect on B. cereus growth with RIA 85% and 80%, respectively. Phenyllactic acid had a stronger inhibitory effect on P. roqueforti than on A. neoniger at 50 mg/ml MIC. The antipathogenic effects of phenyllactic acid, nisin, and pediocin (alone or in combination, with or without adjuncts) were stronger than their mold-controlling effects. A combination of such biopreservatives with EDTA is a suitable alternative to the preservatives used to improve the shelf life of perishable food products.