In the world of agriculture, food safety and water quality are paramount concerns for farmers, state and federal agencies, irrigation districts, and ultimately consumers. Addressing these challenges requires dedicated researchers who understand the importance of practical implementation. Meet Dr. Channah Rock, a passionate scientist and self-proclaimed "boots-on-the-ground" researcher. With her extensive career, she has made significant strides in translating research into tangible solutions for growers. Beyond her scientific pursuits, she finds great fulfillment in mentoring and inspiring young minds to explore the sciences and apply their knowledge where it matters most. Join us on this enlightening journey as we delve into her impactful work and its profound implications for the agricultural community.

Channah Rock, Ph.D., is an Endowed Professor in Extension Fresh Produce Safety at the University of Arizona in the Department of Environmental Science and with Arizona Cooperative Extension. She is involved in several projects relating to microbial evaluation of water quality and environment for the protection of public health. If you’ve heard the terms “outbreak” or “E. coli” associated with fresh produce, she was involved, playing a vital role in assisting stakeholders and regulatory agencies in unraveling the mysteries surrounding these incidents. Simply put, she provides farmers and industry with the knowledge, skills, tools, and awareness to make informed decisions about their production practices including their water resources, to protect public health.

Based at the Maricopa Agricultural Center in Maricopa, Arizona, Dr. Rock hosts a Statewide Water Quality and Food Safety Research and Extension Program.

We’ve run into each other over the years, and I’ve always been keen to ask her more about her work and her projects. I’m also especially proud of her since she earned her master's degree and Ph.D. at Arizona State University. Remember, I’m always the one that says, “This Sundevil (me), loves her wildcats.” But occasionally, I can’t help but put a plug-in for my own alma mater. And, in the words of Dr. Rock, “One gave me the degree, the other pays the bills.”


Arizona Agriculture: What’s your front and center project(s) that our farm and ranch members should be interested in? 


Rock: While we have been working on providing the industry with an improved understanding of agricultural water treatment for several years, our current projects have a strong emphasis on harvest practices and their impact on food safety. 

Recently, the FDA has announced a “sampling assignment” focused on swabbing of harvest machines to identify potential food safety risks including the presence of Listeria sp., Salmonella, and pathogenic E. coli. We're working on providing data that can improve cleaning and sanitation practices while highlighting the importance of harvest foremen and workers in ensuring a safe food supply.


Arizona Agriculture: As a microbiologist and water quality expert who studies pathogens and organisms like E. coli, you often speak about issues of water quality and public health. What are we getting right in Arizona agriculture and where do we need to improve?


Rock: I often tell folks that those of us in Cooperative Extension have the best jobs in the world. We are fortunate that we get to work with stakeholders who are as passionate about growing safe and sustainable crops as we are about research! 


The local produce industry here in Arizona is very forward-thinking and supports not only funding research that can improve their production practices but also the implementation of that research. It is very easy for me to talk to food safety professionals in the industry about our research findings related to effective agricultural water treatment, or best management practices around compost, or crop product management. 


Where we can improve is linking what we teach to food safety professionals to an overall risk assessment for a farm or ranch. We often tend to compartmentalize each aspect of crop production, e.g., water treatment, soil amendments, animal intrusion, and more. The more that we can do to understand how changes in one area will impact food safety in another area, the safer our produce will be. 


Arizona Agriculture: On another front, you recently presented genome sequencing for the fresh produce industry. What does this mean and what does it have the potential for as we move forward in this industry?


Advancements in whole genome sequencing allow us to trace organisms from sick patients back to their source in the food supply or environment. We are currently working with funding from the Center for Produce Safety to validate “field-ready” methods that enable the rapid identification of potential links between organisms found in agricultural water sources/production fields and those found in animals or the general population. 


By shortening the time it takes to make these linkages, these technologies provide quicker decision-making capabilities to protect public health. Part of the adoption of new technologies is getting our stakeholders comfortable with those advancements. As part of the project, we are not only validating the tools, but also teaching growers and other food safety professionals through a series of workshops about those tools, how to use them, and what to do with the data to improve their use.  


Arizona Agriculture: Your newest research project began this year where you’ll study microbiological risk assessment in preharvest ag water treatment systems for leafy greens. Talk about it. 


Rock: One of our newest projects, also funded by the Center for Produce Safety, focuses on quantifying the risk reduction impacts of agricultural water treatment on leafy greens. While we have a good understanding of the impact of water treatment on pathogens and indicator organisms in water, we lack data on the benefits of agricultural water treatment for organisms already present on the plant’s surface. 


Through this research, we aim to quantify the impact of water treatment on pathogens that have already been deposited on plant tissue, resulting from factors like animal intrusion, contaminated crop products, or rouge dust from adjacent land. Ultimately, we will provide the industry and regulatory community with risk reduction metrics to tell us the added benefit of water treatment beyond the reduction of bacteria in the water alone.


Arizona Agriculture: Through your social media outreach you are out and about in the fields, with the farmers, and engaged with the labor teams. I get a hunch you love what you do and are fully engaged with the ag sector. Why? What inspires you?


Rock: I am truly passionate about what I do. The agricultural community inspires me every day. Working closely with stakeholders and witnessing their dedication to safe and sustainable crop production is a privilege. By being in the field, interacting with growers, and experiencing their commitment firsthand, I gain a deep understanding of their needs. Their respect for the land, and each other, and their determination to provide safe and nutritious products for their families and the wider community is truly inspiring.


Arizona Agriculture: From your perspective as a scientist, what makes Arizona agriculture so special?


Rock: While the love for agriculture is common among farmers worldwide, what sets Arizona agriculture apart is its strong sense of community. Yuma holds a special place in my heart. Despite being competitors in the marketplace, growers and food safety professionals come together to support the best interests of their industry and consumers. They readily assist each other, share information, and collectively work towards raising the standards for all. Inclusive education, information sharing, and collaborative learning are integral to the Arizona and Yuma agricultural community.


Arizona Agriculture: I get a vibe that while you like science in general and whether in the lab or presenting, you love being out in the field. Talk about this.


Rock: You’re absolutely right. I love the field! Watching the sunrise over a field of lettuce or standing at the ditch bank in the desert is an incredible experience. The fieldwork drives my dedication to my research and Cooperative Extension role. Transforming hard work in the field into valuable data that benefits the agriculture industry is immensely gratifying. 

When I can bring a grower to one of my field trials, explain our research, and witness their excitement about new findings that can enhance their practices, I know I am fulfilling my purpose. Fortunately for me, building a team of equally passionate students and staff who share in this work adds to the joy.


Arizona Agriculture: What’s been the most exciting discovery, experience, and even advances for you in your field of research in Arizona?


Rock: Some of the most significant findings that we have made in recent years are related to an improved understanding of the variability in agricultural water treatment effectiveness across a production field. 


While that may not sound earth-shattering, it has impacted both local (AZ LGMA) and federal (FDA FSMA) food safety regulations. Because of our research alongside industry, growers and food safety managers now have a better understanding of how to collect water samples, when to collect water samples, how to interpret their water quality data, and how ultimately to improve their water treatment effectiveness. This has helped to establish science-based standards for water quality and food safety in agriculture supporting new Food and Drug Administration (FDA) regulations and trained more than 1,000 growers or food safety professionals since 2018. 


Additionally, we established a first-of-its-kind risk assessment for food-borne illness due to pathogenic microorganisms for the leafy green industry, stimulating regulatory dialogue. Finally, we developed a tool adopted and used nationally as part of mandated grower training, now translated into Spanish, the Ag Water app, and Online Calculator (, helping to protect and secure Arizona’s 70,000 acres of leafy greens, $800 million per year in farm income, in addition to fresh produce from across the nation and the world.


Arizona Agriculture: What’s the big hurdle in your research field? What seems insurmountable but possible that has the potential to keep you up at night?


Rock: One of the biggest challenges we face in fresh produce safety is the fact that the industry grows their products in an open environment where not everything can be controlled. Pathogens are part of the natural environment. 

For example, pathogens can be found in every surface water source if you look hard enough. The challenge lies in prioritizing efforts to best protect public health and ensure safe food production with limited resources. Growers face difficult decisions about their production practices, and while food safety standards are increasing, consumers are often unwilling to pay higher prices for improved food safety practices. Scaling research to support industry advancements while understanding the potential limitations is a significant challenge.


Arizona Agriculture: At 30,000 feet, what makes Arizona produce production so important and so special?


Rock: The continued success of Arizona produce production is due to the strong commitment of the community. The dedication of industry, academia, and government to adopt new practices, innovate tools, and guide implementation ensures that Arizona remains a vital part of the nation's food supply.


Arizona Agriculture: Despite water, food safety, and cost management challenges, do you remain hopeful about agriculture in Arizona and why?


Rock: Absolutely! Arizona agriculture plays a critical role in the nation's food supply and will continue to do so. While the industry may evolve over the next 20 years, the commitment of stakeholders to adopt new practices, support research, and ensure public health protection gives me confidence in the continued success of agriculture in Arizona.


Arizona Agriculture: What have I not asked that I need to?


Rock: These were great questions, and I appreciate the opportunity to discuss my research and passion for agriculture in Arizona!

Editor's Note: This article first appeared in Arizona Farm Bureau's August 2023 issue of Arizona Agriculture.