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Fruit Produce Facts English
Plum
Recommendations for Maintaining Postharvest Quality
Carlos H. Crisosto, Elizabeth J. Mitcham, and Adel A. Kader
Maturity & Quality
Maturity Indices In most of the cultivars growing in California, harvest date is determined by skin color changes that are described for each cultivar. A color chip guide has been designed to determine maturity for each cultivar.
Measurement of fruit firmness is recommended for cultivars where skin ground color is masked by full red or dark color development before maturation.
Maturity & Quality Photos
Title: Ripeness Stages Photo Credit: Don Edwards, UC Davis
Temperature & Controlled Atmosphere
Optimum Tempertures -1.0 to 0°C (30.5-32°F) 90-95% R.H; an air velocity of approximately 50 CFM is suggested.
To calculate heat production multiply ml CO2/kg·hr by 440 to get BTU/ton/day or by 122 to get kcal/metric ton/day. Rates of Ethylene
*The lower end of this range is for mature but unripe fruit; higher values are for ripe fruit. Most of the plums harvested at the California Well-Mature stage (higher than US-Mature) will ripen properly without exogenous ethylene application. Ethylene application to fruit harvested at the US-Mature maturity will only ripen the fruit more uniformly without speeding up the rate of ripening. However, for the slow ripening plum cultivars, expgenours application of ethylene (100 ppm for 1-3 days at 20°C/68°F) is needed for even ripening. These cultivars are Angeleno, Black Beaut, Casselman, Late Santa Rosa, Kelsey, Nubiana, Queen Ann, Red Rosa, and Roysum. The major benefits of CA during storage/shipment are retention of fruit firmness and ground color. Decay incidence has not been reduced by CA of 1-2% O2 + 3-5% CO2. CA conditions of 6% O2 + 17% CO2 are suggested for reduction of internal breakdown during shipment, but its effectiveness depends on cultivar, preharvest factors, market life and shipping time. Market life varies among cultivars and it is strongly practices on affected by temperature management. Maximum market life is obtained when fruit are stored at approximately 0°C (32°F). Maximum market life varies from 1-8 weeks. Because internal breakdown is the main limitation to market life, minimum postharvest life occurs when fruit is stored at 5°C (41°F). Temperature & Controlled Atmosphere Photos
Title: CA Effects (1) Photo Credit: Don Edwards, UC Davis 
Title: CA Effects (2) Photo Credit: Don Edwards, UC Davis 
Title: CA Effects (3) Photo Credit: Don Edwards, UC Davis
Disorders
Physiological and Physical Disorders [For more information, see our publications “ Fruit Ripening & Ethylene Management ”, and “ Peaches, Plums, and Nectarines-Growing and Handling for Fresh Market ”, available for purchase using our Order Form.] Disorders Photos
Title: Alternaria Rot (1) Photo Credit: Don Edwards, UC Davis 
Title: Alternaria Rot (2) Photo Credit: Don Edwards, UC Davis 
Title: Chilling Injury (1) Photo Credit: Don Edwards, UC Davis 
Title: Chilling Injury (2) Photo Credit: Don Edwards, UC Davis 
Title: Freezing Damage Photo Credit: Don Edwards, UC Davis 
Title: Hail Damage Photo Credit: CDFA 
Title: Methyl Bromide Injury Photo Credit: USDA 
Title: Sulfur Dioxide Injury Photo Credit: Don Edwards, UC Davis 
Title: Vibration Bruising (1) Photo Credit: Don Edwards, UC Davis 
Title: Vibration Bruising (2) Photo Credit: Don Edwards, UC Davis
Date
May 1996 |
Use of Materials
The UC Postharvest Technology Center grants users permission to download textual pages (including PDF files) from this World Wide Web site for personal use or to reproduce them for educational purposes, but credit lines and copyright notices within the pages must not be removed or modified.
Except for these specified uses, no part of the textual materials available on the UC Postharvest Technology Center Web site may be copied, downloaded, stored in a retrieval system, further transmitted or otherwise reproduced, stored, disseminated, transferred or used, in any form or by any means, except as permitted herein or with the University of California's prior written agreement. Request permission from UC Postharvest Technology Center. Distribution for commercial purposes is prohibited.
The information in this fact sheet represents our best understanding of the current state of knowledge at the time of the latest update, and does not represent an exhaustive review of all research results. Links to any of these UC Postharvest Technology Center pages are permitted, but no endorsement of the linking site or products mentioned in the linking page is intended or implied by such a link.
How to Cite
Author(s) names. Initial publication or update date (located at the top). Title. Link to the specific Produce Fact Sheet webpage (Accessed date)
Example: Cantwell, M. and T. Suslow. 2002. Lettuce, Crisphead: Recommendations for Maintaining Postharvest Quality.
http://ucanr.edu/sites/Postharvest_Technology_Center_/Commodity_Resources/Fact_Sheets/Datastores/Vegetables_English/?uid=19&ds=799 (Accessed January 18, 2014).
