ATLANTA, GA — Tuesday kicked off day one of the Center for Produce Safety’s (CPS) 2023 Research Symposium. This year’s symposium is being held at the Grand Hyatt Atlanta in Buckhead, GA. 

This is the Center for Produce Safety’s 14th Annual Research Symposium.

The two-day event features discussions and presentations on the latest advancements in produce safety research, as well as opportunities to network with professionals from industry, government and academia.

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Day one began with a panel titled, “Research 101: Maximizing your time: How to get the most out of the research” featuring panelists: Suresh DeCosta, Lipman Family Farms; Martin Wiedmann, Cornell University; Drew McDonald, Taylor Fresh Foods; and was moderated by Laura Strawn, Virginia Tech. Panelists discussed how the hundreds of attendees can benefit from the symposium and the research being presented.

A sampling of research presented:

Risks of dust associated with produce contamination

University of Arizona researcher Kelly Bright presented findings from her team’s study titled “When the E. coli hits the fan! Evaluating the risks of dust associated produce cross contamination” at symposium’s on Tuesday morning session.

The research focused on the role of dust as a vehicle for microbial dispersal and produce contamination by pathogens. While the evaluation of water and soil-borne pathogens is common, the study aimed to fill the gap in understanding the risks associated with dust and soil-borne particulates.

The study proposed three objectives. Firstly, to assess the transfer of foodborne pathogens to produce surfaces in different regions of the United States. Secondly, to investigate the impact of humidity on dust deposition on produce and the survival of pathogens within the dust. Lastly, to analyze dust particulates from animal operations for fecal contamination biomarkers and the presence of pathogens.

The results of the study indicated that detecting pathogens directly from air samples was challenging. No E. coli or Salmonella were found in the samples, possibly due to desiccation stress. However, higher numbers of high-performance liquid impinger samples recovered molecular targets more efficiently than high-volume dry air filter samples.

The study also observed that dust contaminated by animal feeding operations could travel long distances, with positive cow fecal markers detected more than 5 miles away. Increasing wind and dust in the air corresponded to a higher presence of bacteria and fecal indicators.

Bright emphasized the need for larger studies with more samples and a variety of animal feeding operations to further understand the risks to fresh produce fields and other food growing operations. The research team also recommended using a risk-based approach, such as implementing physical barriers or buffer crops near animal operations, monitoring wind and dust levels, and conducting additional product testing or delaying harvest when conditions pose a higher risk of dust contamination.

Microfluidic paper-based analytical devices for microbial source tracking

Purdue University researcher Mohit Verma presented his project on “Field evaluation of microfluidic paper-based analytical devices for microbial source tracking” to his audience of professionals from industry, government and academia on Tuesday.

The study focused on the risk of animal-source contamination on fresh produce, which can lead to foodborne illnesses. Current methods for assessing this risk have limitations in terms of cost, time, and being lab-based. Verma’s project aimed to develop a novel tool that could be used in the field to assess the risk of animal-source contamination within an hour, compared to traditional methods that can take days.

The tool would be based on detecting DNA from feces of animals and would be able to differentiate between different animal hosts such as swine, poultry and ruminants. It would use paper-based devices similar to pregnancy tests, which are affordable, portable and easy to use.

To validate the tool, it would be tested in various conditions including controlled lab settings, animal feeding operations and during the growing and harvesting seasons in the field. The project aimed to provide crop operations — including fields of leafy greens — with a new method to assess the risk of contamination, ultimately leading to safer food and fewer foodborne illnesses.

The proposal outlined two main objectives. The first objective was to establish a baseline by determining the levels of fecal and pathogenic contamination naturally present in fields, on harvest tools and around animal feeding operations. The second objective was to optimize the microfluidic paper-based analytical device by testing samples in both lab and field settings.

The project would utilize Bacteroidetes as indicator organisms for fecal contamination, as they can differentiate between different host types. By targeting specific DNA sequences within their genome, the tool would be able to detect these bacteria. It would also be capable of detecting Shiga toxin-producing E. coli and Salmonella.

The final report provided insights into the use of Bacteroidedales DNA as a biomarker to detect the risk of fecal contamination. The study found varying levels of Bacteroidedales DNA around fresh produce operations, with higher concentrations near animal operations. The report suggested combining the developed tool with metadata and threshold values to convert the concentration into a risk rating for specific operations.

The symposium’s full agenda can be found here.

About CPS
The Center for Produce Safety (CPS) is a 501(c)(3), U.S. tax-exempt, charitable organization focused exclusively on providing the produce industry and government with open access to the actionable information needed to continually enhance the safety of fresh produce.

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