University of California

Vegetables English

Cucumber

Recommendations for Maintaining Postharvest Quality

cucumber011
Trevor V. Suslow and Marita Cantwell

Department of Plant Sciences, University of California, Davis

Maturity & Quality

Maturity Indices

Cucumbers are harvested at a range of developmental stages. Depending on cultivar and temperature, the time from flowering to harvest may be 55 to 60 days. Generally fruit are harvested at a slightly immature stage, near full size but before seeds fully enlarge and harden. Firmness and external glossiness are also indicators of a pre-maturity condition. At proper harvest maturity, a jellylike material has begun to form in the seed cavity.

Quality Indices

Table or slicing cucumber quality is primarily based on uniform shape, firmness and a dark green skin color. Additional quality indices are size, freedom from growth or handling defects, freedom from decay, and an absence of yellowing.

U.S. grades are Fancy, Extra 1, No. 1, No. 1 Small, No. 1 Large and No. 2.

Industry grades and specifications follow the packing conventions SuperSelect, Select, Small Super, Small, Large, and Plain. These terms have no enforceable contractual value.

Maturity & Quality Photos

cucumber_color_rating_scales

Title: Color Rating Scales

Photo Credit: Adel Kader, UC Davis

cucumber_usda_color

Title: USDA Color

Photo Credit: Adel Kader, UC Davis

Temperature & Controlled Atmosphere

Optimum Temperature

10-12.5°C (50-55°F)

Storage of cucumber is generally less than 14 days as visual and sensory quality deteriorate rapidly. Shriveling, yellowing, and decay are likely to increase following storage beyond two weeks, especially after removal to typical retail conditions. Short term storage or transit temperatures below this range (such as 7.2°C (45°F)) are commonly used but will result in chilling injury after 2-3 days.

Chilling Injury. Cucumbers are chilling sensitive at temperatures below 10°C (50°F) if held for more than a day to 3 days depending on temperature and cultivar. Consequences of chilling injury are water-soaked areas, pitting and accelerated decay. Chilling injury is cumulative and may be initiated in the field prior to harvest. Cucumber varieties vary considerably in their susceptibility to chilling injury.

Optimum Relative Humidity

95%

Rates of Respiration

Temperature 10°C (50°F) 15°C (59°F) 20°C (68°F) 25°C (77°F)
ml CO2/kg·hr 12-15 12-17 7-24 10-26

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.
Respiration varies widely above 10°C due to different stages of maturity. Less mature cucumbers have higher respiration rates.

Rates of Ethylene Production

0.1-1.0 µl/kg·hr at 20°C (68°F)

Responses to Ethylene

Cucumbers are highly sensitive to exogenous ethylene. Accelerated yellowing and decay will result from low levels (1-5 ppm) of ethylene during distribution and short-term storage. Do not mix commodities such as bananas, melons and tomatoes with cucumber.

Responses to Controlled Atmospheres (CA)

Controlled or modified atmosphere storage or shipping offer moderate to little benefit to cucumber quality maintenance. Low O2 levels (3-5%) delay yellowing and the onset of decay by a few days. Cucumber tolerates elevated CO2 up (CA) to 10% but storage life is not extended beyond the benefit of reduced levels of O2.

Temperature & Controlled Atmosphere Photos

cucumber_chilling_injury

Title: Chilling Injury (1)

Photo Credit: Yilmaz Ilker, Postharvest Consultant, New Jersey 

cucumber_chilling_injury2

Title: Chilling Injury (2)

Photo Credit: Yilmaz Ilker, Postharvest Consultant, New Jersey 

cucumber_chilling_injury3

Title: Chilling Injury (3)

Photo Credit: Don Edwards, UC Davis

cucumber_ethylene_damage

Title: Ethylene Damage

Photo Credit: Adel Kader, UC Davis

Disorders

Physiological and Physical Disorders

See Chilling Injury.

Freezing Injury. Freezing injury will be initiated at -0.5°C (31°F). Symptoms of freezing injury include a watersoaked pulp becoming brown and gelatinous in appearance over time.

Harvesting should be done by cutting free of the vine rather than by tearing. "Pulled end" is a quality defect used in establishing grade quality.

Bruising and compression injury are very common when attention to careful harvest and handling practices are not followed.

Pathological Disorders

Diseases are an important source of postharvest loss, particularly in combination with chilling stress. A large list of bacterial and fungal pathogens cause postharvest losses in transit, storage, and to the consumer. Alternaria spp., Didymella Black Rot, Pythium Cottony Leak, and Rhizopus Soft Rot are common disorders.

Special Considerations

Cucumbers are often treated with approved waxes or oils to reduce water loss, reduce abrasion injury and enhance appearance.

Yellowing during the postharvest period is a very common defect. Harvesting fruit at an advanced stage of development, exposure to ethylene, or storage at too high temperature all cause yellowing.

Disorders Photos

cucumber_defects

Title: Cucumber Defects

Photo Credit: Adel Kader, UC Davis

cucumber_fusarium_decay

Title: Fusarium Decay

Photo Credit: Adel Kader, UC Davis

Date

May 1997

Use of Materials

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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.

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).

College of Agricultural & Environmental Sciences
Postharvest Technology Center
Department of Plant Sciences

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