Effects of Ionizing Radiation on Postharvest Fungal Pathogens

Abstract

Postharvest diseases cause losses in a wide variety of crops around the world. Irradiation, a useful nonchemical approach, has been used as an alternative treatment for fungicide to control plant fungal pathogens. For a preliminary study, ionizing radiations (gamma, X-ray, or e-beam irradiation) were evaluated for their antifungal activity against Botrytis cinerea, Penicillium expansum, and Rhizopus stolonifer through mycelial growth, spore germination, and morphological analysis under various conditions. Different fungi exhibited different radiosensitivity. The inhibition of fungal growth showed in a dose-dependent manner. Three fungal pathogens have greater sensitivity to the e-beam treatment compared to gamma or X-ray irradiations. The inactivation of individual fungal-viability to different irradiations can be considered between 3–4 kGy for B. cinerea and 1–2 kGy for P. expansum and R. stolonifer based on the radiosensitive and radio-resistant species, respectively. These preliminary data will provide critical information to control postharvest diseases through radiation.

Effect of Electronic Cold-PasteurizationTM (ECPTM) on Fruit Quality and Postharvest Diseases during Blueberry Storage

“…Further, sensitivity of irradiation also can differ among various plant pathogens. Using an in vitro assay, inactivation of B. cinerea, Penicillium expansum, and Rhizopus stolonifer was observed at irradiation doses of 3-4 kGy and 1-2 kGy, respectively [47]. The maximum dose of irradiation of 1.0 kGy in our study may not have been sufficient to decrease postharvest decay pathogens.…”

Effect of phytosanitary irradiation and methyl bromide fumigation on the physical, sensory, and microbiological quality of blueberries and sweet cherries

“…In our study, however, 0.4 kGy did not lower mold counts as compared to the control suggesting that the D values for these organisms on cherries is higher than 0.4 kGy. In fact, Jeong and colleagues determined D values for pure cultures to be between 3 and 4 kGy for B. cinerea and 1 and 2 kGy for P. expansum and R. stolonifera and several studies show that decay in blueberries is not impacted even at 3.0 kGy . Drake and Neven saw increased defects and softening in Bing cherries irradiated at 0.9 kGy so it is likely that at the doses required for significant mold reduction, quality may be compromised.…”

“…The end of blueberry and cherry shelf‐life is often characterized by growth of fungi such as Monilinia fruticola , Rhizopus stolonifer , and Botrytis cinerea . Irradiation at 2–3 kGy has been shown to inhibit growth of these spoilage organisms, but the effect of phytosanitary dose levels on fungal growth, and hence shelf‐life, is not known.…”

Antifungal effect of gamma irradiation and sodium dichloroisocyanurate against Penicillium expansum on pears

“…Jeong et al . () recently reported that some postharvest fungal pathogens showed different morphological changes after GI. This raises the possibility that key factors in fungal spore may be associated with radioresistance.…”