University of California

Fruit Ripening & Ethylene Management

Spring 2021 Virtual Workshop

(Details will be available early in 2021)

Enrollment information for the 2021 workshop will be available soon.




Who Should Attend

This workshop is intended for shippers, fruit handlers (wholesale and retail) and produce managers who are involved in handling and ripening fruits and fruit-vegetables. The workshop focuses on how to increase profits by reducing losses at the receiving end, and delivering ready-to-eat, delicious fruits and fruit-vegetables to the consumer.

Participating in this workshop is one way to earn credits towards completing the Produce Professional Certificate.



Topics included (2019)

  • Importance of ripening programs
  • Ripening fruit and fruit-vegetables
  • Ripening facilities & equipment
  • Fruit development-ripening
  • Maturity and quality relationships
  • Biology of ethylene production
  • Sensory quality attributes and measurement
  • Temperature management
  • Retail temperature storage conditions
  • Retail displays and handling
  • Demonstrations
  • Tools to control ripening and senescence
  • Ethylene inhibition and control
  • Designing/controlling a ripening program
  • Physiological disorders and other losses


  • Sensory
  • Quality measurements
  • Environmental equipment

Instructors (2019)

  • Mary Lu Arpaia, Subtropical Horticulturist, UCR
  • Jeff Brecht, Postharvest Physiologist, University of Florida
  • Christine Bruhn, Food Marketing Specialist Emerita, UCD
  • Marita Cantwell, Specialty and Fresh-cut Vegetable Specialist, UCD
  • Irwin Donis-Gonzalez, Postharvest Engineering Specialist, UCD
  • Dennis Kihlstadius, Postharvest Consultant, Produce Technical Services
  • Beth Mitcham, Postharvest Pomologist, UCD
  • Mikal Saltveit, Plant Physiologist, UCD
  • Jim Thompson, Postharvest Engineering LLC and UCD Emeritus
  • Florence Zakharov, Postharvest Sensory Specialist, UCD
  • And other industry and academic instructors

group photo 2019

Fruit Ripening Workshop Group Photo 2019


Mary Lu Arpaia, Ph.D.

Arpaia, Mary Lu
As an extension specialist for subtropical fruit, I have both an educational and research program dealing with citrus and avocado postharvest handling. There are two areas related to subtropical fruit postharvest handling in which I conduct research.

The first deals with the role of preharvest management on postharvest fruit quality. A clearer understanding of orchard management’s role is needed to develop strategies that optimize the postharvest life of subtropical fruits. I therefore collaborate in multi-disciplinary projects that examine the role of irrigation, fertilization, plant growth regulators and pest management on postharvest fruit quality.

I also conduct research that examines the response of subtropical fruit to the postharvest environment including temperature during handling and ethylene exposure.  As part of this research effort we have incorporated the use of sensory science procedures to study the impact of handling practices on eating quality.  


Negre-Zakharov, Florence
Florence Negre-Zakharov 

Fruit aroma is generally a complex mixture of a wide range of volatile compounds; however, volatile esters often make the major contribution to the aromas of such fruits as apple, pear, banana, strawberry and cantaloupe. These volatile esters arise from the esterification of alcohols in a reaction catalyzed by alcohol acyl-transferase (AAT) enzymes. Although some AATs have been identified and studied in some fruits, there is still very little known about the entire pathways leading to fruit aroma production and the molecular mechanisms involved in the regulation of fruit volatile production. My research projects focus on investigating the biochemical routes leading to aroma and flavor formation in fruits and vegetables, and how aroma formation is regulated during fruit development and postharvest. The long term goal of this research is to improve the aroma quality of fruits in association with extended shelf life.

For more information on technical content, please contact:

Mary Lu Arpaia Ph.D.
Title: CE Subtropical Horticulturist
Phone: (559) 646-6561


Florence Zakharov
Title: Associate Professor

For more registration information, please contact:

Pam Devine
Title: Administrative Officer
Phone: 530-752-6941





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