Practical Implications Of Food Safety Research
Three produce pros discuss the results from the second annual Center for Produce Safety Research Symposium.
PMA founded Center for Produce Safety (CPS) in 2007, along with the University of California at Davis, the California Department of Food and Agriculture, and Taylor Farms. PMA will have provided nearly $2.6 million by the end of 2011 to fund the center's operations for its first four years. The association also contributes in kind the work of Dr. Bob Whitaker, PMA's chief science and technology officer, who chairs the center's Technical Committee and is a member of its Executive Committee.
Here, Whitaker talks with two produce industry leaders, Dave Corsi, VP of produce for Rochester, N.Y.-based Wegmans Food Markets and past chairman of PMA's board of directors, and Joe Pezzini, COO of Castroville, Calif.-based Ocean Mist Farms and chair of PMA's Produce Safety, Science and Technology Committee, about the recently held Produce Research Symposium and the implications of the research results.
Whitaker: The second annual CPS Research Symposium was held in Orlando, Fla., on June 28, 2011, and presented 16 CPS-funded research programs from seven institutions. A food safety-focused audience from across the fresh produce supply chain participated in cross-disciplinary discussions of the research findings' real-world value. The symposium demonstrated a profound and critical return on the investment the industry and PMA have made in this arena. Dave, why was the symposium so successful?
Corsi: Food safety continues to be our most pressing issue. The symposium represents a truly unique opportunity to address priority research for the industry and translate it into best practices. The inclusive nature of this forum — uniting retailers, foodservice operators, growers, regulators, world-class scientists and everyone in between — ensured viewpoints from all segments.
Whitaker: And let me add, the specific nature of these research projects yielded some great information the industry has been lacking. But, like beauty, the research value is in the eyes of the beholder. It's now up to individual companies to find out what the research said and incorporate it into best practices. Dave, why does this research matter to retailers, and how difficult is it for retailers and other industry companies to understand what was presented at the symposium?
Corsi: Retailers are the last link in the food safety chain before the consumer. All our efforts to ensure the safety of the food we handle are moot if we don't have a safe product to start with. Issues affecting the entire production and distribution system certainly matter to us. The practical discussion woven into the symposium resulted in easily digestible information. Companies can review the projects by accessing reports from the symposium, abstracts of these research programs, and peer reviews on the CPS or PMA websites, www.cps.ucdavis.edu or www.pma.com. At Wegmans, we partner with a wide scale of farming operations, large and small. The research can be valuable to any size of operation, and we can assist in spreading the word on the latest research findings.
Whitaker: While we encourage people to look at the abstracts and glean for themselves the application of the results, we can offer a summary of some of the key learnings from the symposium. A number of the projects looked at wash water. Joe, what were some of the noteworthy results?
Pezzini: Of particular interest, more resilient wash-water chemistries are emerging. So far, research indicates a next-generation commercial product, T128, may act by preserving active chlorine under conditions where increasing organic loads in wash-water systems would normally deplete chlorine. Over time, as organic load builds in wash water using traditional sodium hypochlorite wash water treatment, the amount of active chlorine sanitizer decreases, owing to interactions with organic materials. This condition may permit pathogens, if present, to survive in the wash water and cross-contaminate produce moving through the system. T128 works by protecting active chlorine as organic loads increase, in the end diminishing cross-contamination risks. While preliminary work has been performed using leafy greens, it necessitates watching to see what applications T128 may have with other commodities.
Whitaker: The research also looked at how organic load is a critical factor in wash water systems. Aqueous chlorine dioxide (C102) has been suggested as a wash-water sanitation approach for several fruit and vegetable wash systems, including tomatoes. Experiments conducted in tomato flume systems and dump tanks show that high organic loads building up over time, specifically in tomato dump tank water, severely impact an operator's ability to maintain one-to-five-parts-per-million chlorine dioxide as mandated by T-GAP metrics. It is crucial to monitor organic load in wash water to ensure proper levels of sanitizers are available to prevent cross-contamination.
Pezzini: The discussion on how a “brush-bed wash” system for tomato washing may hold promise was also significant. The system uses a combination of roller brushes and a water spray containing a sanitizer. The two-step combination of physical brushing and a water/sanitizer spray was shown to result in greater than a thousand-fold reduction in surface microbes. This pilot-scale process may also mitigate the risk of cross-contamination compared to water-bath systems. Obviously, a great deal of scientific and operational testing still needs to be done to validate this approach.
Whitaker: This research presented on wash-water systems represents the natural progression in the development of effective food safety practices. Industry's well-intentioned efforts to set measurable parameters for tomato wash-water and dump-tank systems were based on the best available data and technical innovation. As the industry and the research community fill information gaps, more effective options, systems and monitoring devices will emerge. Joe, what else do you think was particularly remarkable?
Pezzini: All the research related to the survivability of pathogens was quite valuable. For example, one of the projects showed that attenuated E. coli O157:H7 does not survive in Salinas Valley production environments. The data clearly points out the importance of performing risk assessments on fields prior to harvest, since potential contamination events closer to the time of harvest may be of higher priority to identify than events further from harvest. This is an important area of research to continue to follow.
Whitaker: Furthermore, research indicated that plant genetics and physiology may play a role in pathogen survival. Two research programs hinted at the role plant genetics may play in pathogen contamination and survival on spinach leaves and tomato fruits. It is unclear whether it may be possible to select for genetic resistance to human pathogens in the future, but a better understanding of plant-human pathogen interactions will help inform future research and risk management strategies.
Pezzini: There was also discussion concerning what we still need to learn about norovirus. Bob, can you explain what was presented?
Whitaker: The Centers for Disease Control (CDC) ascribes a high proportion of foodborne illness to norovirus. Data presented at the symposium indicates norovirus can be taken up into plant tissues. While these experiments were conducted using very high inoculum levels under laboratory conditions that may not actually reflect field or process-level conditions, they do suggest that the norovirus may survive for up to five days in plant tissues. Much more research is required in this area to better describe the risk norovirus represents to fruit and vegetable production. Dave, what else did you find useful?
Corsi: One of the most unique sessions suggested how beneficial our collective produce industry data could be. Our industry currently collects vast amounts of food safety-related data every day — from food safety audits, to water testing and sanitation verification, to product testing. This industry data may provide valuable insights for risk assessment and management, and guide future research. Of course, hurdles regarding the proprietary nature of the data and the ability to evaluate related observations must be overcome. The produce industry needs to continue to work toward the development of mechanisms to make food safety data available to the research community.
Whitaker: The industry needs this type of research, and it needs you to support CPS now. CPS' research is working to answer our most pressing food safety questions and close gaps in the industry's knowledge base. While we have made many gains on the food safety front, we must remain hard at work finding even more answers in the name of continuous improvement.