Evaluation of microbial potential and ripening behavoiur of preclimacteric bananas following gamma irradiation

Abstract

ABSTRACT:The current study was carried out to evaluate the effects of gamma irradiation on the epiphytic microflora and ripening process of the green Dwarf Cavendish bananas harvested at the three-quarter stage of the maturity. The mature green bananas were irradiated using Cobalt-60 as the source of irradiation at different dosages of 0.5, 0.75 and 1.0 kGy. The mean life of both the experimental and control group of fruits was analyzed under ambient conditions. For all the treatments the microbial potential, the decay percent and the ripening behavior of the fruits were recorded. Results revealed that the applied radiation doses reduced the decay incidence, delayed ripening process and greatly inhibit the microbial growth (total bacterial and fungal count) thereby enhancing the shelf life of bananas. Irradiation dose of 1.0 kGy was found to be the most effective dose to positively maintain the stored bananas under ambient conditions. The mean life of bananas was extended by 14 days. The identification of the enteric bacteriaeaceae through API 20 E strips revealed the presence of Shigella sonnie on the fruit surface along with Escherichia coli and a nonfermentor spp. The dominant spoilage causing fungi identified were Aspergillus niger, Aspergillus flavus, Collotrichum musae, Fusarium oxysporum,Mucor spp, Lasiodiplodia theobromea and Rhizopus stolonifer.

INVESTIGATION OF THE SHELF LIFE OF BANANA ‘MAS’ (Musa acuminata Colla) USING GAMMA IRRADIATION

“…This result was supported by Prakash (2019), who stated that the ripening process of the banana can be delayed by using a low dose of gamma radiation of 0.2-0.4 kGy. Research is done by Abdullah et al (2017) also proved that nonirradiated bananas started to decay after two weeks of storage and irradiated bananas with a dose of 1.0 kGy were remained healthy for up to 28 days that become superior one for controlling decay percent. Thus, after two weeks, all the samples were completely decayed.…”

“…The decay of banana fruits during storage is observed and recorded every day for 5 weeks after irradiation. The decay is determined with a brown spot visible on banana Mas peel and the result is expressed as the percentage of decayed fruits (Abdullah et al, 2017).…”

“…However, the bananas are perishable that metabolically active, undergoing ripening and senescence processes that must be controlled to delay ripening (Mahajan et al, 2014). The fresh banana produce is potentially contaminated by microbes and pathogens during cultivation, harvesting, transporting, packaging, storage and selling to the consumers which manifests a severe risk in food safety and decreases the shelf life of bananas (Abdullah et al, 2017). Therefore, it cannot be preserved for a long time after harvesting which contributes to the limitation in exporting bananas (Abdullah et al, 2017).…”

“…Gamma radiations have proved to be more effective than an x-ray, as it is non-thermal technology, legal, low cost, maintaining freshness, quality, nutrition and leaves no harmful residue (Handayani & Permawati, 2017). The advantages of gamma irradiation compared to the other methods is it provides more efficient and homogenous penetration power in the tissue, short radiation time and does not increase the fruit temperature (Abdullah et al, 2017). It can increase the shelf life of a banana by eliminating pathogenic bacteria, disinfect fresh fruits and vegetables as a postharvest quarantine treatment and reduce or eliminate microorganisms (Abdullah et al, 2017).…”

“…The advantages of gamma irradiation compared to the other methods is it provides more efficient and homogenous penetration power in the tissue, short radiation time and does not increase the fruit temperature (Abdullah et al, 2017). It can increase the shelf life of a banana by eliminating pathogenic bacteria, disinfect fresh fruits and vegetables as a postharvest quarantine treatment and reduce or eliminate microorganisms (Abdullah et al, 2017). This study aims to evaluate the application of gamma irradiation as the preservation method and its effect on the shelf life of banana Mas.…”