Latest Research Findings Hit On Produce Safety Priorities

Because it provides inherently healthy, nutritious foods, the fresh produce industry is uniquely positioned to help solve the nation’s obesity epidemic. To do so, consumers must have confidence in the safety of the fresh fruits, vegetables, and nuts they eat and feed their families.

Following a large and deadly outbreak of foodborne illness linked to fresh spinach in 2006, the U.S. produce industry couldn’t wait for government or other direction. After finding significant knowledge gaps and a lack of data needed to build risk- and science-based produce safety programs, the industry created the Center for Produce Safety (CPS) in 2007.

CPS at 10 Years: Funding Science, Finding Solutions, Fueling Change

Just 10 years old in 2017, CPS has already paid out $23.6 million to finance 138 projects at 40 institutions in 28 states and 5 countries, according to its 2017 annual report. Most of the research projects it funds move from concept to results and clearinghouse in about a year. More than 330 people from across the universe of fresh produce safety stakeholders attended CPS’s 2017 Research Symposium; attendance has increased every year since the symposia began.

CPS answers crucial produce-specific food safety questions, providing science-proven results that are ready to use in the real world. CPS has already achieved so much, because it has successfully fostered a truly unique partnership, bringing together leaders from industry, government, and the scientific and academic communities.

“CPS works because it is a collaboration of the best and brightest who volunteer their time, expertise, and financial support to make CPS a success,” says Tim York, chair of CPS’s Board of Directors, and president of the foodservice industry’s Markon Cooperative.

Many CPS contributors’ corporate culture goes beyond investing their money. They also commit the human and other resources to ensure CPS gets it right.

“The scene has replayed itself many times: Someone I am talking to will refer to Center for Produce Safety using ‘our CPS,’ ‘ours,’ or ‘we.’ They state their ownership, loud and clear,” concurs Bonnie Fernandez-Fenaroli, CPS’s executive director.

In just 10 years, CPS has made a substantial mark on the fresh produce industry.

“Ten years ago, our industry intuitively recognized that food safety was important, but over the last decade CPS has provided evidence that has underscored the need to prioritize and invest in it,” says Hank Giclas of the industry trade group Western Growers. “Today, our industry is more open to making changes to improve food safety preventive controls because we have acknowledged that food safety is a critical industry mission.”

One of CPS’s most important early accomplishments has been to build strong ties with the research community, including cultivating the next generation of produce safety researchers.

“CPS is fabulous about getting researchers, including research students, involved and making connections,” reports Dr. Martin Wiedmann, a CPS-funded researcher from Cornell University. “And no other group does research symposia with industry as successfully.”

CPS’s funding comes from across the fresh produce supply chain and from grants from major specialty-crop producing states. Its 2017 annual report can be accessed on CPS’s website by early summer 2018.

CPS works to identify produce safety hazards, then funds research that develops that data as well as potential science-based solutions that the produce supply chain can use to manage those hazards. While two foodborne illness outbreaks in the first half of 2018 associated with leafy greens demonstrate the industry still has challenges to meet, CPS has grown into a unique public-private partnership that moves most of the research it funds from concept to real-world answers in about a year.

Each June, CPS hosts a symposium to report its latest research results to industry, policy makers, regulators, academia, and other produce safety stakeholders. Key learnings from the 2017 symposium have just been released on topics including water quality, cross-contamination, and prevention. A few highlights from those key learnings are summarized here, and for the full details, you can download the Key Learnings report from CPS’s website.

Know Your Water
Irrigation water is a potentially significant contamination hazard for fresh produce while it is still in the field. While CPS research has revealed many learnings about agricultural water safety in its 10 years, many questions still remain. Meanwhile, the U.S. Food and Drug Administration (FDA)’s proposed Food Safety Modernization Act (FSMA) water testing requirements—which offers some challenges for producers in specific production regions—recently raised even more questions.

New CPS research illustrates the risks of irrigating with “tail water” from runoff collection ponds. With water becoming a precious resource in drought-stricken areas, the objective was to learn if tail water might be recovered and used for irrigation. We learned that differences among pond sites—for example, water sources, climate, ag management practices—can strongly influence the chemistry and microbiology of the water. Further, water pH can influence disinfection treatment strategies.[1]

CPS research continues to investigate tools for irrigation water testing, looking specifically at sample volumes,[2] and searching for better water quality indicators and indexing organisms including harnessing next-generation DNA sequencing.[3] Following a CPS-organized colloquium on ag water testing in late 2017, FDA subsequently announced it would revisit FSMA’s ag water requirements, and postponed compliance.

Bottom line, CPS research demonstrates that growers must thoroughly understand their irrigation water before they can accurately assess cross-contamination risk. CPS’s findings clearly point to the need to take a systems approach, to understand and control the entire water system to help achieve produce safety. Long term, this may mean prioritizing research into ag water disinfection systems to better manage contamination hazards that can also operate at rates needed for field production.

Cross-Contamination Can Happen across the Supply Chain
While conceptually and anecdotally the fresh produce industry knows that food safety is a supply chain responsibility, research is needed that documents the role of the entire supply chain to keep fresh produce clean and safe from field to fork. At the 2017 CPS Research Symposium, research reports were presented focusing on cross-contamination risks from the packinghouse to retail store display.

In the packinghouse, CPS-funded research found that wash systems can effectively control cross-contamination on fruit, when proper system practices are implemented.[4] Post-wash, CPS research involving fresh-cut mangos also demonstrated that maintaining the cold chain is critical to controlling pathogen populations.[5] Across the cantaloupe supply chain, CPS studies show food contact surfaces—for example, foam padding—are potential points of cross-contamination.[6] See the full 2017 Key Learnings report for details, as these brief descriptions only scratch the surface of this research.

CPS studies clearly demonstrate that food safety is a supply chain responsibility—a message that must be internalized from growers and packers to transporters, storages, and retailers to commercial, institutional, and home kitchens. While translating this research into reality will present engineering and operational challenges, our new understanding of produce safety demands it.

Verifying Preventive Controls
The produce industry must know that its preventive controls are in fact effective. That said, validation can be tricky. If validation research doesn’t mimic the real world, industry ends up fooling itself about whether its food safety processes work—and the human consequences are real.

Numerous scientists presented research at the 2017 CPS Research Symposium that validates various preventive controls, from heat treating poultry litter[7] to pasteurizing pistachios[8] to validating chlorine levels in wash water systems.[9] Some researchers effectively used nonpathogenic bacteria as a surrogate in their validation studies, while another is working to develop an avirulent salmonella surrogate, and another. Wang used actual Escherichia coli O157:H7 (albeit in a laboratory).

Importantly, CPS research finds that the physiological state of a pathogen or surrogate, and pathogen growth conditions themselves, are critically important to validation studies.[10] Meanwhile, suitable surrogates have been identified for some applications, the search continues for many others.

Author(s): Bob Whitaker, Ph.D.

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