The present study was carried out in Department of Agricultural Microbiology, University of Agricultural Sciences, Bengaluru to investigate the microbial populations responsible for spoilage in fruits, vegetables and oilseeds. The specific spoilage organisms in food samples were isolated and identified using 16s rRNA sequencing for bacterial isolates and ITS sequencing for fungal isolates. The enzymatic spoilage potentials of the isolates were studied qualitatively to understand the mechanisms of infection. The pathogenic abilities of the selected isolates were also assessed by inoculating them into fruits and subsequently re-isolating them from symptomatic tissues. The sequencing results revealed the dominant species present in spoiled food samples were Klebsiella oxytoca, Enterobacter mori, Serratia marcescens, Bacillus subtilis, B. inaquosorum, Penicillium citrinum, Alternaria alstroemeriae, Aspergillus awamori, Aspergillus welwitschiae and Aspergillus aflatoxiformans. The pathogenicity assay confirmed the isolated bacteria and fungi as potential phytopathogens that can induce rots in fruits including apple, papaya and tomato. The findings suggest that implementing improved management practices in food samples, such as protection from mechanical injuries or reducing microbial inoculum, may result in lowering post-harvest losses during storage and transportation

Spoilage microorganisms, 16s rRNA sequencing, ITS sequencing, Phylogenetic analyses, Pathogenicity test

This study identified and characterized the major microflora associated with spoilage and post-harvest losses in fruits, vegetables and oilseeds, which are also pathogenic to humans. All bacterial and fungal isolates, except for Bacillus spizizenii, were confirmed as pathogens causing fruit rots in the respective fruits. These microbes were able to produce extracellular enzymes to hydrolyze starch, cellulose and pectin revealing the possible mechanisms of infection. This represents an initial step in comprehending the disease incidence in food samples. The severity of the disease was found to be related to higher inoculum concentrations, which resulted in rapid spoilage. To mitigate such issues, natural practices were suggested such as the removal of infected plant material or application of chemical or biological antimicrobials, etc. These measures can decrease the inoculum concentration, thereby reducing the chances of infection. Further research is being conducted on bio-preservation as a potential strategy that could be employed to reduce the spoilage occurrence in fruits, vegetables and oilseeds during storage and post-harvest stages.

Rashmi S., Suvarna V.C., Bharath Kumar N. and Veena S. Anil (2024). Exploration of Microbial Flora Associated with the Spoilage of Fruits, Vegetables and Oilseeds. Biological Forum – An International Journal, 16(9): 14-21