Antimicrobial Activity of Binary and Ternary Mixtures of Vanillin, Citral, and Potassium Sorbate in Laboratory Media and Fruit Purées

Abstract

The susceptibility of Escherichia coli, Salmonella enteritidis, Saccharomyces cerevisiae, and Zygosaccharomyces bailii to binary and ternary mixtures of potassium sorbate (KS), vanillin (V), and citral (C) was evaluated according to the Berenbaum experimental design, in laboratory media. For some V/C combinations, KS inhibitory concentrations were determined in agarized melon and mango purées by the spiral gradient endpoint (SGE) method. In laboratory media, inhibitory antimicrobial combinations were generally additives. For the yeasts, some synergistic effects were observed. All Berenbaum mixtures which resulted inhibitory in laboratory media were confirmed in the fruit purées. When the SGE method was used, several inhibitory ternary mixtures were found. The lowest inhibitory KS concentrations, estimated for a given V/C combination, corresponded to the bacteria assayed in melon purée. Z. bailii was not inhibited at any condition. Some synergistic antimicrobial combinations (595 ppm V + 251 ppm C + 8 ppm KS in melon and 280 ppm V + 123 ppm C + 8 ppm KS in mango purées) could be useful to achieve a desired inhibitory effect in fruit purées while reducing their concentrations.