Progress 11/01/01 to 04/30/05
Outputs
4d Progress report. This report serves to document research conducted under a reimbursable agreement between ARS and the Binational Agricultural Research and Development Fund on the subject of the use of ethanol as a treatment of table grapes to reduce postharvest decay. Additional details of research can be found in the report for the parent CRIS 5302-43000-032-00D Emerging technologies to maintain postharvest quality and control decay of fresh commodities. In 2004, we quantified and modeled the toxicity of brief exposures of spores of Rhizopus stolonifer, Aspergillus niger, Botrytis cinerea and Alternaria alternata to heated, aqueous ethanol solutions, and we showed how ethanol could be used in practical applications to table grapes. Control of these fungi, all of which are common postharvest decay pathogens of fresh grapes and other produce, is important to reduce decay losses. Logistical, second-order, surface- response models were prepared to model the mortality
of each fungus. Ethanol and heat combinations were synergistic; control of spores of these fungi could be accomplished with much lower temperatures and ethanol concentrations when combined compared with either used alone. Ethanol treatment was evaluated for use on table grapes, and effective rates, grape quality, residues and other practical aspects were examined. This work shows that ethanol, a simple natural compound, can be used as an effective agent to control these postharvest fungal pathogens, in particular gray mold caused by B. cinerea on table grapes.
Impacts
(N/A)
Publications
|
Progress 10/01/03 to 09/30/04
Outputs
4. What were the most significant accomplishments this past year? D. This report serves to document research conducted under a reimbursable agreement between ARS and the Binational Agricultural Research and Development Fund on the subject of the use of ethanol as a treatment of table grapes to reduce postharvest decay. This project is related to the in-house project (CRIS 5302-43000-029-00D) to develop safe alternatives to synthetic fungicides. In 2004, we quantified and modeled the toxicity of brief exposures of spores of Rhizopus stolonifer, Aspergillus niger, Botrytis cinerea and Alternaria alternata to heated, aqueous ethanol solutions. Spores of the fungi were exposed to solutions containing up to 30% (v/v) ethanol at 25-50C for 30 s, then their survival was determined by germination on semisolid media. Logistical, second-order, surface-response models were prepared for each fungus. Subinhibitory ethanol concentrations at ambient temperatures became inhibitory
when heated at temperatures much lower than those that cause thermal destruction of the spores by water alone. Ethanol and heat combinations were synergistic. Control of spores of these fungi could be accomplished with much lower temperatures and ethanol concentrations when combined compared with either used alone. Botrytis cinerea and A. alternata were less resistant to the combination than A. niger or R. stolonifer. This work shows that ethanol, a simple natural compound, can be used as an effective agent to control these postharvest fungal pathogens.
Impacts
(N/A)
Publications
|
|