Thesis
Evaporative cooling: sunburn suppression benefits and influence on microbial survival
Washington State University
Master of Science (MS), Washington State University
12/2015
Handle:
https://hdl.handle.net/2376/100126
Abstract
Sunburn is a disorder with significant economic implications to the apple industry. In the State of Washington at least 10% of apple cullage is attributed to sunburn each year. The use of overhead evaporative cooling (EC) decreases the apple surface temperature leading to a decreased likelihood of sunburn development. In 2012 and 2013, two field trials were conducted in Eastern Washington to analyze the sunburn incidence of Gala, Golden Delicious and Fuji apples under two treatments EC and untreated control (UC) and two canopy locations (high and low). Packout analyses were conducted based on sunburn data results, for the three varieties in both years, using different crop load scenarios. Using open source irrigation water for EC treatment can pose a serious threat to human health if the water is found to be contaminated. To evaluate this risk, a field inoculation examination was conducted in 2014 to assess generic E. coli die-off rates under commercial orchard settings. Weather data were collected to investigate possible relationships between environmental conditions and bacterial die-off rates. In both years the use of EC diminished sunburn incidence, except for Fuji in 2013. In 2012, EC decreased sunburn incidence by 8.1% for Fuji, 18.3% for Gala and 0.7% for Golden Delicious. In 2013 Golden Delicious and Gala untreated fruit had 10.2% and 1.6% more sunburn overall than treated fruit, respectively. Untreated Fuji had 3.5% less sunburn overall than treated. The higher percentage of sunburn on Fuji treated with EC is believed to be caused by the discontinuation of water application too early prior to harvest. Overall, higher canopy location presented more sunburn than fruit in lower canopy positions. Packout analysis results show that EC increased net returns for all varieties on both years, and in all crop load scenarios. Field inoculation results indicate that overall 99.99% of generic E. coli didn't survive the first 24 hours. EC had positive effects regarding the generic E. coli die-off rates for Golden Delicious and combining apple varieties, potentially helping to increase generic E. coli die-off rates, considering the weather and water application rates used on this experiment.
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Details
- Title
- Evaporative cooling
- Creators
- Manoella Cabral Mendoza
- Contributors
- R. Karina Gallardo (Chair)Karen Killinger (Committee Member)Ines Hanrahan (Committee Member) - Washington State University, Horticulture, Department of
- Awarding Institution
- Washington State University
- Academic Unit
- Agricultural, Human, and Natural Resource Sciences, College of
- Theses and Dissertations
- Master of Science (MS), Washington State University
- Publisher
- Washington State University; [Pullman, Washington] :
- Number of pages
- 107
- Identifiers
- 99900525097201842
- Language
- English
- Resource Type
- Thesis