Lab Associates

Bill Biasi

Bill Biasi – Staff Research Associate
1078 Wickson Hall

My role as Staff Research Associate working for Dr. Mitcham involves managing research activities on various types of fruits and nuts to improve overall quality and flavor. I also assist with developing alternative treatments to kill various insect pests so that more products can be successfully exported. In addition, I am the manager of the Postharvest Pilot Plant in Wickson Hall which is shared by several postharvest researchers.

Veronique Bikoba

Veronique Bikoba – Lab Assistant
1098 Wickson Hall

My role as a member of Dr. Mitcham’s lab focuses on postharvest pest control. The goal of my work is to find an alternative to methyl bromide to control various arthropods on harvested commodities, especially fruit. This role involves planning and applying various treatments, including fumigations (vapormate, sulfur dioxide, controlled atmosphere, and methyl bromide), surfactants, and heat treatment; and assessing mortality after treatment. Pests that have been tested include: the black widow spider, light brown apple moth, western flower thrips, bean thrips, omnivorous leaf roller, grape mealy bug, aphid, California red scale, pacific spider mite, two spotted spider mite, Fuller rose beetle, and phylloxera. I maintain the colonies of some of these arthropods. After finding a promising treatment and testing it for produce tolerance, I evaluate the quality of the produce tested. Any successful treatment in our laboratory setting is tested on a commercial scale. I manage the chemical laboratory and train new hires joining the pest management program and anyone needing to use the chemical lab.

Ashley Call

Ashley Call – Junior Specialist
1078 Wickson Hall

As a junior specialist in the Mitcham lab I am involved with a number of different projects.  For instance, I am currently working on a project in which we are testing different irrigation treatments and their effect on postharvest quality and consumer sensory evaluation of berries (strawberry, blueberry and blackberry).  Due to California’s long-term drought and escalating water prices in some areas of the state, there is a great need to reduce water usage in berry production without sacrificing yields, quality and consumer preference.  In addition to research, my responsibilities to the lab include postharvest quality evaluations of various types of fruits, laboratory analysis of samples, statistical data analysis, and presentation of data. I am interested in plant biological research in general and agricultural research specifically.  I received my BS in Biology at Appalachian State University in Boone, NC and my MS in Plant Biology at North Carolina State University in Raleigh, NC.  

Sandra Escribano

Sandra Escribano – Postdoctoral Scholar
3012 Wickson Hall

Working as a Postdoctoral Scholar in the Mitcham Laboratory, I am fascinated by the research studies on harvest maturity, storage conditions and flavor quality of fruits and vegetables. I am keenly interested in understanding and controlling physiological pathways of fruit ripening required to maintain fruit quality. Some of my current research goals are: explore the impact of 1-MCP and ethylene on shelf-life and sensory quality of ‘Bartlett’ pears, study the role of cell wall pectin chemistry on cellular Ca2+ partitioning and its effects on tomato fruit susceptibility to calcium deficiency disorders and blossom-end rot, and explore the sensory quality and consumer acceptability of new California cherry varieties at different ripeness stages.

Ngoc Nham

Ngoc Nham - PhD Student (Graduate Group of Horticulture and Agronomy)
1106 Wickson Hall

My field of research is postharvest physiology, focusing mainly on European pears. My research aims to understand molecular pathways that regulate pear ripening and ultimately determine biomarkers that can be utilized to detect pear ripening capacity. I earned my B.Eng. in Biochemical Engineering from Hanoi University of Technology in Vietnam and have received the Vietnam Education Foundation scholarship to study at the University of California at Davis. Graduate student life has been very exciting so far. I enjoy this growing-up time when I learn to balance demanding pipetting protocols in the lab with challenging moves on the dance floor.

Ephrem Rukundo

Ephrem Rukundo – PhD Student
1106 Wickson Hall

My current research project focuses on improving both nutritional and sensory quality of dried fruits. While there is a superiority of the quality attributes for fruits dried at very low temperature (freeze drying), this method is expensive. Other methods such as solar drying are weather dependent and exposes fruits to pests, microbes and to high temperatures which can be detrimental to nutritional quality.

This project is investigating a new method of drying fruits at room temperature using air dehumidification by zeolite beads. The zeolite beads are made of ceramic with 3Å pores that can absorb up to 25% of their weight in water molecules from the atmosphere. With a lifetime of more than 1,000 uses, the beads can be regenerated by heating to a temperature above 200 ̊C.

We will evaluate the drying efficiency of zeolite beads and the nutritional quality and sensory quality of tomato and mango fruit dried with beads and solar drying. The nutritional quality will be evaluated in terms of vitamin A, C and E for dried tomatoes and mangoes. The sensory quality will be evaluated based on: Color, soluble solids, titratable acidity, texture, crispness, chewiness, flavor etc.

Addie Abrams

Addie Abrams – Graduate Student

I am interested in the postharvest control of insect pests.  My thesis work is focused methyl bromide alternatives for the control of European grapevine moth.  I am currently investigating the cold tolerance of European grapevine moth at cold storage temperatures, and the potential of cold storage as a postharvest control for insect pests of California table grape. 

My research is conducted inside of laboratory space at the UC Davis Contained Research Facility, a level 3 agricultural quarantine, where I also manage several colonies of high risk insect pests including European grapevine moth, Brown marmorated stink bug and Western cherry fruit fly. 

Marisa Jung

Marisa Jung – Administrative Assistant
1047 Wickson Hall

I am employed as the Administrative Assistant to Dr. Mitcham. As her assistant I perform many tasks, which include providing general administrative and clerical support including mailing, scanning, faxing and copying for Dr. Mitcham. Also, I managed Dr. Mitcham’s business calendar; scheduling and coordinating meetings, appointments, and travel.

Mitcham Lab 2014 Undergraduate Student Assistants

Undergrad Student Assistants

former lab associates

Azia Hasan-Cherry

Azia Hasan-Cherry – Former Administrative Assistant

I worked as Administrative Assistant to Dr. Mitcham, performing many tasks to assist the Director of this program. My duties included providing general administrative and clerical support including mailing, scanning, faxing and copying for Dr. Mitcham. I personally managed Dr. Mitcham’s business calendar; scheduling and coordinating meetings, appointments, and travel. I currently work for the Horticulture Innovation Lab, at the University of California, Davis.

Alfonso Lopez

Alfonso Lopez – Former Junior Specialist

I was born in Cordoba, Spain on February 3rd, 1987. I studied at Cordoba University in 2005. In 2008 I passed one year in Mendelova University of Brno (Czech Republic) and in 2010 I went to Quito, Ecuador with an NGO (MCCH) for my final dissertation.

I was hired to work in Dr. Mitcham’s lab as a Junior Specialist. As a Junior Specialist, I worked with berries and pears and analyzed pre-harvest as well as post-harvest treatments.

Sergio Tonnetto de Freitas

Sergio Tonnetto de Freitas - Former PhD Student and Postdoctoral Associate

My research interest was to better understand the mechanisms involved in Ca++ deficiency development in fruit. These mechanisms can be related to fruit Ca++ uptake and homeostasis in the cell.
I am now working at Embrapa in Brazil.

Malkeet Padda

Malkeet Padda - Former Postdoctoral Associate

Research Focus: Granny Smith apple quality is reduced by two major physiological disorders: superficial scald and bitter pit. These disorders cause great losses to apple growers worldwide. My research projects in the Mitcham Lab focused on exploring the potential use of anaerobiosis treatment as a non-chemical method to control superficial scald and bitter pit in Granny Smith apples.

Dr. Padda currently works for Driscoll’s in Salinas, California.

Dr. Nobuko Sugimoto

Dr. Nobuko Sugimoto – Former Postdoctoral Associate

I received a B.S. in Law in Japan, studied at Michigan State University and received my M.S. in Horticulture working on apple aroma. I continued my work and received a PhD in Horticulture at MSU in 2011. My PhD study was emphasized on branched-chain ester biosynthesis in apple fruit, and I found new genes in a new synthetic pathway and characterized the genes. I joined in Dr. Mitcham’s lab in 2012 as a postdoctoral associate.  My work in the Mitcham Lab focused on the efficacy of 1-MCP.
Dr. Sugimoto currently works for the FAS, USAID in Japan.

Tyann Blessington

Tyann Blessington - Former Graduate Student

Research Focus: My dissertation focused on understanding the vulnerable points and developing for hazard/risk analysis harvest and the processing of walnuts to prevent future outbreaks of foodborne illnesses.

I now work at the Department of Homeland Security, Office of Health Affairs, National Biosurveillance Integration Center, Washington D.C.

warangkana Makkumrai

Warangkana Makkumrai - Former Graduate Student

My thesis investigated the sensory quality of ‘Bartlett’ and ‘Comice’ pears as affected by temperature and ethylene treatments after harvest. The measurement of sensory quality included aroma volatile compounds by GC-MS, texture of fruits by determining cell wall breakdown, and descriptive sensory analysis by a trained panel.

Project Detail: We will evaluate the sensory quality of ‘Bartlett’ pears exposed with ethylene (100 ppm), low temperature (0 °C), and intermediate temperature (10 °C) after harvest to stimulate ripening. The parameters of sensory quality will be determined including trained panel test, change in cell wall composition and aroma volatile production.

Francine Pupin

Francine Pupin – Former Graduate Student

My thesis research developed a quarantine treatment for several pests of citrus (California Red Scale and Western flower thrips) and codling moth of sweet cherries. Both inspect control and product tolerance were tested.

2012 – Master of Science, International Agricultural Development, University of California, Davis. Advisor: Dr. Elizabeth Mitcham

2011 – Postgraduate Certificate in Postharvest Biology Technology, University of California, Davis.

2008 – Bachelor’s Degree in Food Sciences, ESALQ, University of Sao Paulo, Brazil.

2009-’11 – Junior Specialist, Department of Plant Sciences,
University of California, Davis – Dr. Mitcham.

In the Postharvest Technology Center, I researched quarantine fumigation, gas and chemical analysis, fruit quality assessment, data analysis and presentation.

Max Villalobos

Max Villalobos - Former Graduate Student

My thesis research focused on improving fruit quality and reducing postharvest losses by optimizing the use of an ethylene action inhibitor, 1-methycyclopropene or 1-MCP, in California ‘Bartlett’ pears. 1-MCP decreases ripening rates and reduces scald and internal breakdown, two important physiological disorders induced during storage at low temperatures. 1-MCP’s effect on the fruit depends on various factors such as fruit maturity or stage of ripeness at the time of treatment, exposure to ethylene prior to or during treatment, and 1-MCP concentration, among others. I currently work for Valent BioSciences in Costa Rica.

Murillo Cordova Flores

Murillo Cordova Flores - Former Visiting Student

I had an internship here at UC Davis for one year. I won a scholarship from my government, and I was included in the program, Science Without Border/CNPq.

Luis Alejandro Delgado Lendinez

Luis Alejandro Delgado Lendinez - Former Visiting Student

I am from Jaen, South Spain. I finished my Bachelor of Agricultural Engineering in 2011, where I was studying MSc in “Food Chain Systems” at Cranfield University, U.K., during the academic year 2010-2011. At this period of time, I completed my major in Agrifood Industry.

I participated in an internship program as a researcher assistant at UC Davis in the Postharvest Laboratory.  Here, I worked on two projects. One was with strawberries, blueberries, and blackberries to analyze and check quality parameters following production under different irrigation regines.  The other project involved removing the moisture content in fruit using Zeolite Drying Beads.

Aquidauana Miqueloto

Aquidauana Miqueloto – Former Visiting Scholar

I was a visiting PhD student from the University de Santa Catarina in Brazil, working in the Mitcham Lab for one year on my dissertation research.

I my research is investigating the effect of auxin on physiological disorders involving Ca++ deficiency, such as bitter pit in apples and blossom-end rot in tomatoes.

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Joao Paulo Silveira – Former Visiting Scholar

I was a visiting PhD student from the University de Santa Catarina in Brazil working in the Mitcham Lab for one year on my dissertation research. My research interest is to better understand the effect of gibberellin (GA4+7) and gibberellin biosynthesis inhibitor (prohexadione calcium) into the mechanisms involved in Ca++ deficiency development and postharvest quality in apple fruit. As some papers published have been showed, the prohexadione calcium can reduce blossom and rot in tomatoes by the affect in reduce the expression of vacuolar transporters. We are looking to answer the question of: “Has the prohexadione calcium the same behavior in apple as compare with tomatoes?” To better answer this question, we are working with different concentration (gibberellin and prohexadione calcium) and spraying time to find the best treatment and time to spraying the product to get fruit with better quality and without chance of “bitter pit” manifestation. The goals of this work are to reduce the food waste (it is a big problem in our society) and to get information to better understand the bitter pit manifestation and reduce the economic problem that it has been showed into the apple production.

Elena Sanchis Soler

Elena Sanchis Soler - Former Visiting Scholar

I am a PhD student from Spain. In Spain, I am working in Plant Sciences for three months to improve my knowledge in the application of 1-MCP treatments in fresh-cut pears. The aim of this study is to extend the shelf-life of the fruit.  I am working for the Valencian Institute Agricultural Research (VIA). The main aim of my study is to obtain the marketing of fresh-cut persimmons ‘Rojo Brillante’. Among the objectives, I intend to reduce the enzymatic browning of the fruit with the application of antioxidant treatments, packaging with modified atmospheres, and the application of edible coatings with antioxidant capacity, maintaining the physic-chemical and sensorial quality and nutritional properties as well.

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Shinjae Jeon – Former Visiting Scholar

I worked with the Mitcham Lab as a visiting scholar for one year in 2012. Before I came here, I worked in an agricultural research station in South Korea for 15 years. My research interest is to understand the mechanisms of tomato fruit cracking in greenhouse conditions. Also, I conducted analysis of antioxidant capacity in berry fruit.