Exploring Lactic Acid Bacterial Metabolites for Antimicrobial Activity Against Spoilage Organisms of Grapes and Potato

Biopreservation of foods is an alternative and novel method of preservation with increased special interest from consumers.Lactic acid bacteria (LAB) has the potential to restrict the microbial proliferation of foods, thus preventing spoilage and extending their shelf life. The antimicrobial capabilities of lactic acid bacteria are linked to various actions by the production of antimicrobial compounds such as bacteriocins, hydrogen peroxide, organic acids, etc. The study aims to explore LAB from traditional foods for the biopreservation of grapes and potatoes.LAB were isolated from twelve different food samples viz., mango pickle, curd, cumbu gruel, neera, cold rice, finger millet, infant feces, milk, lime pickle, fermented cumbu (grain), fermented cumbuflour and whey water and their cell free metabolites were extracted. A total of thirteen bacteria and seven fungal cultures were isolated from spoiled grapes and potato. An in vitro experiment was conducted to study the antimicrobial activity of LAB metabolites by performing an agar well diffusion assay against the spoilage cultures. The results revealed varied antimicrobial activity of LAB isolates to different spoilage cultures from potato and grapes. Among the LAB isolates, metabolites from curd, cumbu gruel, fermented cumbuflour, finger millet and neera cultures were observed to inhibit more number of spoilage organisms and produced maximum inhibition zone. A consortium was prepared by pooling the metabolites from these promising cultures and assayed for antimicrobial activity which confirmed the above results.