Merced County Cooperative Extension
Merced County Cooperative Extension
Merced County Cooperative Extension
University of California
Merced County Cooperative Extension

Posts Tagged: Pistachios

Five questions with food safety expert, new AAAS Fellow Linda Harris

Linda J. Harris will be inducted as a member of the 2021 class of American Association for the Advancement of Science Fellows during the AAAS annual meeting. Photos courtesy of Linda J. Harris

Professor of Cooperative Extension shares career story, appreciation for UC Davis

After growing up in northern British Columbia, in a remote smelter town called Kitimat (“an 8-hour drive from the nearest McDonald's”), University of California Professor of Cooperative Extension Linda J. Harris embarked on an academic journey that crisscrossed North America and eventually led to her election as a Fellow of the American Association for the Advancement of Science.

AAAS, the world's largest multidisciplinary scientific society and publisher of the journal Science, recently announced the election of its 2021 class, which will be inducted during its annual meeting, Feb. 17-20.

In addition to Harris – a faculty member in UC Davis' Department of Food Science and Technology – four other UC Agriculture and Natural Resources affiliates will be inducted: Helene Dillard, dean of the UC Davis College of Agricultural and Environmental Sciences; Kathryn Uhrich, dean of the UC Riverside College of Natural and Agricultural Sciences; and UC Berkeley Professors Rodrigo Almeida and Paolo D'Odorico.

Harris, a Certified Food Scientist, recently shared her thoughts on the value of extension work, her contributions to the field, UC Davis' support for women in academia, and the arc of her career journey.

Harris was elected as an AAAS Fellow for her contributions to the field of food safety microbiology, especially related to control of Salmonella.

How did you get your start in food science and microbiology?

I was interested in science at an early age. As an undergraduate student at the University of Victoria in Victoria, B.C., I enrolled in biochemistry at the suggestion of my high school biology teacher. In my second year, I switched to the University of Alberta in Edmonton, Alberta and decided to review the course catalog – a paper version! When I got to the section on Food Science, the applied nature of the field just sounded right and I never looked back.

However, I didn't do particularly well in microbiology as an undergraduate student – too much memorization for me. At the end of my B.S. I was ready for a job in the food industry and took the very first job I was offered – ironically enough as a dairy microbiologist in a quality control lab. Thankfully, that job opened my eyes to the possibilities in microbiology. What was memorization turned into something I learned through doing and I was hooked.

Two years later, I was ready to go back to school and contacted a professor of food safety microbiology at the University of Alberta who fortunately had funding for me. During my M.S. degree in food microbiology, he encouraged me to pursue the Ph.D. – which was not something I had ever considered – and that led me to leave Canada and head to North Carolina State University and a Ph.D. in microbiology in the Food Science Department, where I worked on a project related to the fermentation of sauerkraut.

I did have one publication related to food safety during my time at NC State, and when I took my first faculty position back in Canada [University of Guelph in Ontario] I continued to work in food safety, mostly with meat and meat products.

I am so glad that I saw the advertisement for my current position and that I followed my instincts to apply for the job. The opportunities to grow professionally and to work in the food safety area at UC Davis, within the Cooperative Extension network in California, and with collaborators across the U.S., and around the world, have been enormous, and I am extremely grateful for the path that led me here.

Growing up in Kitimat, British Columbia, Harris developed a love for science at a young age.

February 11 is the United Nations-designated “International Day of Women and Girls in Science.” How has UC Davis supported women in your scientific field?

My career in STEM [science, technology, engineering and math] has been very rewarding and many of the gender barriers I faced early on have been addressed. I feel very fortunate to have landed at UC Davis and I am thankful that there is a long history of addressing these barriers at this institution.

When I was hired in 1996, the Department of Food Science and Technology was about 25% women and both the department chair and dean of the college were women. I had never been in a department or college with so many women faculty, including in positions of leadership. It was a very important consideration in my move. Today our department is 50% women and I proudly served for five years as the second woman department chair, from 2016 to 2021.

As a first-generation university graduate raised by a single mother, you have a unique perspective in encouraging young people on their path toward a STEM career. What advice do you have for them?

To those contemplating a career in STEM, I would say: be open to new opportunities and adventures – you never know where they may lead you. Get involved in leadership in any capacity you can from student organizations or around other things that interest you. Skills that you learn with these types of activities will be invaluable to your career.

I am very much an introvert and had to work hard to overcome my fear of public speaking. In addition to leadership roles in student clubs, I joined Toast Masters while working on my Ph.D. These activities had a huge impact on building my confidence and helped influence my career choices.

Through her work as a Cooperative Extension specialist, Harris has been able to understand firsthand the food-safety needs across California.

In the AAAS Fellows announcement, it says you were elected for “contributions to the field of food safety microbiology, especially related to control of Salmonella and other pathogens in low-moisture foods and fresh produce.” Is that your proudest achievement in the field?

I am most proud of the work described by that short statement especially as it applies to California-grown commodities. I would say that my laboratory is best known for work with the tree nut industry – almonds, pistachios and walnuts, as well as a range of types of fresh produce grown in this state.

My laboratory has worked to understand behavior, movement, prevalence, and especially control of foodborne pathogens like Salmonella during production in the field through harvest and postharvest handling all the way through to consumer practices.

I have been fortunate to have many terrific state, national and international collaborators and an outstanding group of people working in my laboratory as we set the foundation for some of the food safety research in tree nuts and produce. It has been most gratifying to watch the significant growth in these fields of investigation, especially with a new generation of scientists that span the country and beyond.

Another “hat” you wear is UC Cooperative Extension specialist. How have you contributed to food safety knowledge and practices in our communities?

I think you will see that my “hats” are not that different. The research from my laboratory has provided the foundation for several commodity-based, food-safety risk assessments – for almonds, pistachios, and walnuts. And these, in turn, have been used in support of regulations or helped guide implementation of safer food industry practices. Our research has also informed several publications aimed at consumer handling of fresh fruits and vegetables and has been cited in regulations pertaining to fresh produce safety. It is gratifying to see our research being used.

My research and extension work are very integrated. One feeds the other. Because I have been able to interact with stakeholders (especially integral to my position as a Cooperative Extension specialist), I have been able to understand firsthand some of the pressing food-safety issues and challenges in California. These stakeholder interactions have largely formed the basis for most of my research and extension grant proposals over the years. The collaborations that have resulted from extension activities have opened doors and access to many unique opportunities for sample collection and research exploration.

Posted on Thursday, February 10, 2022 at 8:46 AM
Tags: AAAS (1), almonds (3), Fellow (1), Food Safety (48), Food science and technology (2), Linda J. Harris (1), pistachios (4), Q&A (1), Salmonella (6), tree nuts (3), UC Davis (46), walnuts (6)
Focus Area Tags: Agriculture, Food, Health

Pistachio production costs outlined in UC study

Growers considering planting pistachios can refer to a new UC study for estimated production costs and returns.

The popularity of pistachios as a healthy snack continues to drive demand. California's pistachio crop was valued at $1.94 billion in 2019, according to the California Department of Food and Agriculture.

For growers considering planting an orchard, the costs and returns of establishing and producing pistachios in the southern San Joaquin Valley are outlined in a new study by UC ANR's Agricultural Issues Center, UC Cooperative Extension and the UC Davis Department of Agricultural and Resource Economics.

“New growers use this information to create their budget for production loans for their bank,” said Jeffrey Gibbons, plant manager of Setton Pistachio of Terra Bella. “Owners use this information so they can be assured their farm managers are not overcharging them for farming costs. Farm managers use this information to see how they compare to the industry. Setton Pistachio uses this information to project budgets for future planting scenarios.”

UC Cooperative Extension specialists and farm advisors routinely refer people interested in planting pistachios to the cost study.

The first pistachio irrigation in March replenishes the water in the root zone and prepares the system for use during the season. That first irrigation includes costs for use of the utility vehicle, labor for cleaning the filters, repairing the lines and monitoring all the emitters. Photo by Phoebe Gordon

“I use this every time I have a new grower,” said Louise Ferguson, UC Cooperative Extension specialist in the UC Davis Department of Plant Sciences and co-author of the study. “It not only gives a good estimate of establishment and production costs, and projected net returns, but ensures no details are missed in planning. It is an invaluable template for pistachio production.”

Elizabeth Fichtner, UC Cooperative Extension orchard systems advisor for Kings and Tulare counties, agreed. “The cost study documents are one of the first resources I assemble for new growers.”

The new study estimates the costs and returns of establishing and producing pistachios using low-volume drip irrigation in the southern San Joaquin Valley. The hypothetical orchard is planted at 128 trees per acre, with an expected life span of 40 years.

The authors describe the assumptions used to identify current costs for pistachio establishment and production, material inputs, cash and non-cash overhead and a ranging analysis table, which shows profits over a range of prices and yields.

Combined mechanical and hand pruning pistachio trees begins after the orchard achieves full bearing in year 12 or 13. A mechanical pruning company is hired to top the trees every year and to hedge half the trees every other year.

"Pistachio growers, potential future growers, land leasers, appraisers and loan officers benefit from detailed and current information included in the studies,” said Craig Kallsen, UCCE citrus and pistachio farm advisor for Kern County. 

Gibbons said, “Setton Pistachio refers potential growers to this information as they determine if they want to plant pistachios. Setton Pistachio appreciates this information if it is current. If it is too old, it is not reliable, and there is no other good source for unbiased pistachio development information.”

For a grower, deciding not to plant pistachios based on information in the cost study can be just as economically valuable as deciding to plant pistachios based on the cost study, said Kallsen. 

“The information in the cost study can prevent a grower from making a million-dollar mistake by planting a crop that is not suitable for their soil, water availability or for an economic reason not related to crop environment/adaption suitability such as length of time to first harvest or high cost of establishment,” he said.

Reliable estimated costs for a crop grown mostly in California may be hard to find from a source other than UC. This study was co-authored by 17 UCCE farm advisors and specialists and a pomology professor at California State University, Fresno, with input from growers.

“This study summarizes the knowledge learned and used to build California's pistachio industry from 40,000 acres in the 1970s to over 400,000 acres and a 1.1-billion-pound crop in 2020,” Ferguson said.

Types of cultural practices and timing will vary among pistachio orchards within the region and from season to season due to variables such as weather, soil and pest pressure.

The new study, “Sample Costs to Establish and Produce Pistachios, Low-Volume Irrigation, San Joaquin Valley South - 2020” can be downloaded for free from the UC Davis Department of Agricultural and Resource Economics website Sample cost of production studies for many other commodities are also available on the website. 

“UC cost studies are always something I alert potential growers to when they are considering whether to plant an orchard,” said Phoebe Gordon, UC Cooperative Extension orchard crops advisor for Madera and Merced counties. “New growers have expressed to me a few times that they find the cost study useful.”

For an explanation of calculations used in the study, refer to the section titled Assumptions. For more information contact Donald Stewart, University of California Agriculture and Natural Resources, Agricultural Issues Center, Department of Agricultural and Resource Economics, at (530) 752-4651 or To discuss this study with a local UC Cooperative Extension advisor, find the UC Cooperative Extension office in your county at

Posted on Thursday, March 18, 2021 at 10:53 AM
Focus Area Tags: Agriculture

By the bagful: pistachios and milk

A Canadian grocery market sells California pistachios (foreground) and milk in bags (background).
While visiting my brother in Toronto this summer, we stopped by a grocery store and I was struck by two things: pistachios and milk in bags.

Stacked high in the back corner were bags of California pistachios – a reminder of how prominent a producer the Golden State is and a sign of the marketing power of its largest pistachio processor, Paramount Farms. The United States is the world’s leading pistachio producer, and 99 percent of the country’s crop comes from California.

Pistachios are California’s third-biggest nut crop, behind almonds and walnuts, and the state’s sixth-leading agricultural export, with markets spanning from Canada to China.

To help continue to improve production, the pistachio industry is turning to the University of California. In January, the California Pistachio Research Board announced it will donate $1.5 million to support a UC Cooperative Extension specialist to conduct nut and fruit disease research. This specialist position will help UC Agriculture and Natural Resources fulfill its mission as well as serve the pistachio industry’s needs.

UC research plays a key role in keeping California the nation’s leading agricultural state. Partnerships such as the one with the Pistachio Research Board – and previous ones with the California Rice Research Board and California Table Grape Commission – represent a new funding model to extend that role.

On the dairy side, California is known for happy cows; eastern Canada is known for bagged milk. Yes, milk is sold in bags of three, each 1.33 liters. My sister-in-law likes the bags because the packaging is more environmentally friendly than plastic jugs. You even can purchase specially designed pitchers for dispensing bagged milk. The key is cutting the tip of the bag properly, so it can pour smoothly – not too slow and not too fast. It’s an interesting concept, but a little messy. Will milk bags catch on in California? I think that will be a tough nut to crack.

Posted on Tuesday, October 1, 2013 at 1:09 AM
  • Author: Alec Rosenberg
Tags: exports (1), milk (6), Pistachios (4)

Nuts contribute protein, fiber and healthy fat to diet

Two free publications on nuts have recently been published by ANR — Nuts:  Safe Methods for Consumers to Handle, Store, and Enjoy and Nuts:  Safe Methods for Home Gardeners to Harvest, Store, and Enjoy.

Both publications outline the nutritional benefits of eating nuts, including information from the FDA affirming that:

  • Including nuts in a diet low in saturated fat and cholesterol may help reduce the risk of heart disease.

  • Almonds, pecans, pistachios, and walnuts contribute to health through their protein, dietary fiber and unsaturated fat.

The consumer publication includes a handy table outlining optimal freezer and refrigerator storage times for a variety of nuts as well information on nut allergies, nutrition and resources for recipes.

Home gardeners with nut trees will find useful information on harvest times and methods, hulling and drying procedures, safe handling procedures, storage, and nutrition information for almonds, chestnuts, pecans, pistachios and walnuts.

Inside both publications is a discussion of recent bacterial outbreaks in nuts and the steps producers have taken to minimize the risk of exposure to consumers.

Posted on Monday, October 11, 2010 at 8:38 AM
Tags: Almonds (3), pecans (2), pistachios (4), walnuts (6)

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