Evaluation and Exploration of Lactic Acid Bacteria for Preservation and Extending the Shelf Life of Fruit

ABSTRACT

The bio-preservation of fruits using bacteriocinogenic lactic acid bacteria (BLAB) isolated directly from cow dung and curd was an innovative approach. The objectives of this study were to isolate and identify Bacteriocin producing LAB from various curd and cow dung samples, evaluate their antimicrobial effects of BLAB against selected fruits spoiling and pathogenic microorganisms in vitro. LAB was isolated using MRS media. The well-diffusion bioassay was used to screen for Bacteriocin-Like Inhibitory Substance (BLIS) producing LAB Salimicrobium Bacillus, Paenibacillus and Lactobacillus. BLIS producing LAB were tested against 25 fruit flora of selected fruits. These LABs were also tested against Escherichia coli, Staphylococcus aureus, Bacillus cereus, Pseudomonas aeroginosa, Proteus vulgaris, Salmonella typhi, Serritia spp, Xanthomonas campestris, and also against Aspergillus flavus, Aspergillus nigar, Fusarium, Alternaria, Saccharomyces cerevisiae using the diffusion bioassay plate method. The antagonistic activity was also studied against pathogenic fruit flora which has been isolated from fruits. These BLISs showed a wide range of antibacterial activity against tested, fruit-spoilage and fruit-borne pathogens and able to extend the shelf life of fruits. Bacteriocinogenic LAB present in curd and cow dung may have potential to be used as bio-preservatives of tested fruits.