Effects of organic acids to prolong the shelf-life and improve the microbial quality of fresh cut broccoli florets

Abstract

This study was conducted to evaluate the effectiveness of a combination of specific organic acids for disinfecting fresh cut broccoli floret samples contaminated with Listeria monocytogenes serotype 1/2b and Salmonella enterica serovar Typhimurium. In addition, the effects of organic acids on the microbial load of broccoli samples during storage at +4 degrees C were determined for 7 days. The organic acids tested were acetic, benzoic, sorbic, fumaric, malic, tartaric, lactic and succinic acids and the concentrations used were 1 and 2% (w/v and v/v). L. monocytogenes and S. Typhimurium were grown on the selective media before the contamination. The broccoli samples were dipped first into the pathogen solutions containing L. monocytogenes and S. Typhimurium, then into the organic acids and subsequently counted on Oxford agar and bismuth sulphite agar, respectively. The broccoli samples dipped into the organic acids without pathogen culture were also investigated in terms of total mesophilic aerobic microorganisms, psychrotrophic microorganisms, Pseudomonas spp., total lactic acid bacteria, Enterobacteriaceae spp. and total yeast-moulds for 7 days stored at 4 degrees C. S. Typhimurium and L. monocytogenes log reductions were determined at between 3 to 3.28 and 2.63 to 2.84 log colony-forming units/g with 1 and 2% of malic acid and between 3.68 to 4.17 and 2.68 to 2.9 log with 1 and 2% of tartaric acid, respectively. The malic, tartaric, lactic, succinic acids and acetic acid in the tested concentrations could be used to inhibit S. Typhimurium and L. monocytogenes and prolong the shelf-life of fresh-cut broccoli.