Doctoral Thesis
Cold plasma treatment of fungal communities to reduce postharvest strawberry spoilage
Doctor of Philosophy (PhD), Murdoch University
2023
Abstract
Globally, approximately 40% of postharvest strawberry losses are due to fungi, predominantly Botrytis cinerea. However, for strawberries in Western Australia, information about postharvest fungal communities is very limited. Cold plasma (CP) and water treated with plasma, or plasma-activated water (PAW), are potential chemical-free treatments to reduce the spoilage of postharvest strawberries. This study used culture-dependent and independent metabarcoding methods to identify the postharvest fungal communities associated with WA-grown strawberries from farms in two growing regions. CP and PAW were then evaluated as possible methods for reducing postharvest fungal pathogens.
A high relative abundance of the fungi Botrytis and Cladosporium and the yeast Rhodoturula were identified from fruit in both regions, at different times in the growing season. The first two are strawberry pathogens and were dominant regardless of identification methods. Using culture-dependent methods (traditional isolations) Mucor was also abundant. CP and PAW were trialled to determine effective treatment times, and CP for 60 s significantly reduced strawberry spoilage (lesions or mycelial growth) without altering the physical or physicochemical properties (firmness, pH and colour) of the fruit. Finally, the ability of CP and PAW to kill surface fungi was further assessed using propidium monoazide which allows only amplification of DNA from living cells. Six days after CP or PAW treatment, there was a significant reduction in the diversity and abundance of live fungi including pathogens in strawberries, except for Rhodotorula and Cladosporium.
In conclusion, diverse fungal communities are associated with postharvest strawberries in WA. CP and PAW effectively controlled some of the postharvest pathogens of strawberries without altering fruit quality. These results are promising and could be useful for the future development of large-scale CP applications for the strawberry industry.
Details
- Title
- Cold plasma treatment of fungal communities to reduce postharvest strawberry spoilage
- Authors/Creators
- Farhana Momtaz
- Contributors
- Kirsty Bayliss (Supervisor) - Murdoch University, Centre for Biosecurity and One HealthGiles Hardy (Supervisor) - Murdoch University, Centre for Terrestrial Ecosystem Science and Sustainability
- Awarding Institution
- Murdoch University; Doctor of Philosophy (PhD)
- Identifiers
- 991005635670307891
- Murdoch Affiliation
- College of Environmental and Life Sciences
- Resource Type
- Doctoral Thesis
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