Compared with other types of fresh produce, broccoli has not often been the focus of food safety-related research, despite the fact that it is commonly served raw in salads, salad mixes, and crudités platters. So, when Cornell M. Eng. student Yuezhi Wu consulted with Produce Safety Alliance Director Betsy Bihn about possible food science-related topics for his Masters in Engineering thesis, Bihn (who had recently signed on as a collaborator with the Eastern Broccoli Project) naturally thought of broccoli. The resulting study is the first to examine transfer rates of E. coli between broccoli and two surfaces commonly encountered in small packing operations. Though preliminary, the results will inform future risk assessments of the broccoli postharvest environment and help identify measures to prevent contamination events.
Wu’s co-authors on the study are his advisor, Cornell Biological and Environmental Engineering Professor Ashim Datta; Bihn; and Extension Specialist Lindsay Springer, a recent Food Science PhD who at the time was working with Bihn. After considering the postharvest surfaces that broccoli typically encounters in a small farm operation, the authors decided that gloved hands and conveyor belts pose the most risk. In a series of experiments with a nonpathogenic strain of E. coli, the team then measured bacterial transfer rates from contaminated broccoli to previously clean glove and conveyor belt material, and from contaminated conveyor belts and gloves to broccoli crowns and stems. To mimic contact between gloved hands and broccoli, small disks cut from nitrile gloves were pressed against broccoli stems or crowns for 5 seconds; to mimic contact with the conveyor belt, broccoli was dropped onto squares of belt material and kept there for 20 seconds.
The researchers found that the transfer rate from contaminated conveyor belt material to broccoli was much higher than the rate of transfer from contaminated broccoli to the conveyor belt. Contaminated glove disks transferred more bacteria to broccoli crowns and stems than contaminated crowns and stems transferred to glove material. Broccoli crowns in particular picked up more bacteria from contaminated gloves than did broccoli stems, which was attributed to the more porous structure of the crown. The authors noted that these results are consistent with studies using other fresh produce, which have found that transfer rates from non-organic surface (like the gloves and conveyor belt) to organic surfaces (broccoli and other vegetables) is typically higher than the reverse. The results emphasize the importance of cleaning and sterilizing conveyors and of sterilizing or replacing gloves frequently. Ultimately, this type of data can be used to construct models that will help growers understand contamination risks and determine the ideal cleaning schedule for their operation.
Wu, Y., L. Springer, E. Bihn, and A. Datta. Quantifying Escherichia coli Cross-Contamination Rates among Broccoli, Conveyer Belt and Glove. https://hdl.handle.net/1813/57072
Small to mid-size growers in the eastern US have trouble finding reliable buyers for their broccoli, even as distributors, wholesalers, restaurants, and others say they cannot source enough regional broccoli to meet demand. While matching specific buyers with specific sellers is beyond the scope of the Eastern Broccoli Project, we recently added a buyer listing webpage that may help the two groups connect. Growers can use the information to discover and introduce themselves to buyers with a declared interest in sourcing eastern-grown broccoli. Buyers who agree to be listed have the opportunity to engage with local and regional suppliers of this popular produce item.
The Eastern Broccoli Project has developed numerous resources to help growers produce high quality broccoli and understand the expectations and challenges of the eastern broccoli supply chain (click on the ‘Resources’ tab of the menu to see some). However, it is up to growers and buyers to forge the good relationships that are critical to sustaining the eastern broccoli industry. The buyer list is intended to help that process by fostering contacts and discussions between entities with complementary interests. Growers are generally advised to secure a buyer early, preferably before they have a crop in the ground. Many buyers (not just the ones on our list) have specific expectations with respect to certifications, seasonal availability, minimum load size, and delivery.
All of the listings have been approved by their respective buyers. Each includes a brief description of the enterprise and the region they serve, along with a contact email address and logo with website link. We expect the list to expand as more companies and food hubs find out about this opportunity to connect with eastern broccoli growers.
Preventing post-harvest contamination of broccoli and other fresh produce is easier when equipment and packing sheds are built with food safety in mind. A new resource developed with support from the Eastern Broccoli project brings the principles of hygienic design to the post-harvest environment to show how incorporating the right features and materials can simplify cleaning and eliminate common hiding spots for pathogens.
Hygienic design is the norm for food processing environments, but surprisingly little attention has been given to applying the principles to post-harvest equipment and facilities that handle raw agricultural commodities. That omission caught the attention of Produce Safety Alliance Director and Eastern Broccoli collaborator Betsy Bihn, who engaged University of Vermont Agricultural Engineer Chris Callahan to develop guidelines that would make it easier for cooling and packing environments to be in compliance with food safety standards. The result is Hygienic Design for Produce Farms, which is available for download from Callahan’s blog and via a link on the Eastern Broccoli Production resource page.
The publication explains the five key principles of hygienic design (visible and reachable surfaces; smooth and cleanable surfaces; no collection points; compatible materials; and preventing contamination) and discusses some of the tools and materials that can be used to implement them in post-harvest operations. The main goals are to eliminate “harborage points” (places where contaminants and pathogens can settle) and to ensure that all surfaces are accessible and suited to regular cleaning and sanitizing. An “On-Farm Hygienic Design Checklist” is included in the publication and is also available in downloadable, stand-alone pdf and Excel formats.
The publication is intended for growers who are constructing or renovating their washing and packing operation. Agricultural equipment manufacturers will also find the publication useful, as it provides insights about the types of equipment improvements their customers need.
As part of their collaboration with the Eastern Broccoli Project, Produce Safety Alliance Director Betsy Bihn and University of Vermont Agricultural Engineer Chris Callahan have developed guidelines for the hygienic design of post-harvest equipment and surfaces in fresh vegetable packing operations. Prior to their efforts, this information was not readily available to growers and packers of fresh produce.
Now Bihn and Callahan are teaming up with Cornell Cooperative Extension Specialist Robert Hadad to host a workshop on Farm Food Safety – Sanitary Design and Practice Considerations. The event will take place on March 27 from 9 am to 4:30 pm in Jordan Hall at Cornell AgriTech, 630 W North St., Geneva, NY 14456.
Topics to be covered include:
Introduction to Produce Safety for the wash/pack facility
Cleaning – the “how’s and why’s”
Sanitizing – “how’s and why’s”
Drying – “how’s and why’s”
Hygienic Design and Practice Considerations
Visible and Reachable Surfaces
Smooth and Cleanable Surfaces
No Collection Points
Tools and Practices
Greens Spinners – Comparison using evaluation checklist
Are you wondering what the implications of new food safety regulations are for broccoli production? Join Eastern Broccoli Food Safety specialists Chris Callahan, Betsy Bihn, and their colleagues on Monday, May 14 at 2 p.m. EDT for a webinar on “Produce Safety for Broccoli Producers”.
Topics will include:
An overview of produce safety
Coverage thresholds and compliance dates
The Food Safety Modernization Act and Produce Safety Rule
Broccoli-specific produce safety considerations
Overview and feedback on educational material development.
You can register for the webinar using the form below. Registration is not mandatory, but it will help us with planning and make it easier for you to get a direct link to the webinar via email. The form also has room for you to list specific questions that you would like to see addressed during the presentation.
The webinar is geared towards growers, but the information will also be useful to buyers, extension specialists, researchers, and others. Registrants will be emailed instructions for joining the webinar by the day of the event.
Powell Smith, a founding member of the Eastern Broccoli team, recently retired from his position as Horticultural Program Team Leader for Clemson Extension to spend more time outdoors beyond the vegetable field. An entomologist with experience in industry and academia, Powell brought insights about southeastern agriculture and the agricultural community to the Eastern Broccoli project and served as lead for project-related Yield trials and outreach in South Carolina. Those responsibilities now transfer fully to Brian Ward, who has been working with Powell since 2016. No word yet on whether Brian will continue Powell’s habit of sharing sunny South Carolina weather reports with snowbound colleagues up north.
We thank Powell for all of his contributions to the Eastern Broccoli Project and wish him a long and joyful retirement. Happy kayaking, Powell!
The Eastern Broccoli Project recently expanded its Quality trial network to include a site in the important winter growing region of northeastern Florida. Lincoln Zotarelli oversees Quality trial plantings that run from October through April at the University of Florida’s Institute of Food and Agricultural Sciences (UF/IFAS) Hastings Agricultural Extension Center (HAEC).
The Hastings location is differs from other Quality trial sites not only in the timing of its production season, but also in the way in which water is managed. The very sandy soils in this region are separated from the underlying aquifer by a clay hardpan that sits within a few feet of the soil surface. This arrangement allows seepage irrigation to deliver water to plants from below the soil surface through the precise management of water table levels. All other Eastern Broccoli Quality trial sites rely on drip or overhead water delivery.
Florida Quality trial plantings this season were transplanted in early October 2017, early December 2017, and mid-February 2018. All three plantings included the same 31 broccoli hybrids that were rated at the four other Quality trial sites (in South Carolina, North Carolina, New York, and Maine) in 2017. Evaluations are complete for the first planting and in progress for the second planting (Photo 1, above). The third planting (Photo 2, at bottom) will undergo evaluation in early spring 2018.
The Hastings trial has already drawn public attention. In November, a group of 30 Florida elected officials touring grower farms in the Tri-County Agricultural area stopped by the UF-HAEC and, as part of their visit, heard a presentation on the Eastern Broccoli project and the importance of the broccoli industry to the northeast Florida economy. In December, an overview of the broccoli project and its efforts to identify new cultivars adapted to Florida conditions was presented to and discussed with 34 attendees of the station’s 2017 Cole Crop field day.
The Hastings site conducts the last set of plantings in the 14-month Eastern Broccoli Quality trial cycle that begins in February of the previous year. Already, the next Quality trial cycle has begun in Charleston, SC, where seed for a new set of trial entries was sown in February for transplant in mid-March.
The US Vegetable Laboratory in Charleston, SC received a visit this past August from Secretary of Agriculture Sonny Perdue, who toured the facility and expressed his support for agricultural research, including the Eastern Broccoli Project.
The clip below, from RFD-TV via YouTube, shows some highlights from the tour. Our colleague Mark Farnham, who heads the broccoli breeding program at the Lab, appears in several shots. Quality trial leader and Clemson CREC Research Scientist Brian Ward supplied the broccoli seedlings and rating charts shown at 1:31, and Ward can be seen discussing the project with Purdue at 2:02.
An Eastern Broccoli Yield trial in South Carolina will soon be ready to evaluate. Trial leaders Brian Ward and Powell Smith oversaw transplant of several broccoli cultivars on the farm of a commercial grower in Saluda County, SC. The broccoli was transplanted onto plastic-mulched raised beds on 5-foot centers with 10-inch in-row spacing and 12 inch between-row spacing. The photos below show small crowns forming in broccoli plants.
Earlier in the season, the same beds and plastic were used to produce peppers; planting broccoli following another crop on plastic lets growers spread the cost of the mulch over more than one crop and is a common practice in the southeast.
All three Eastern Broccoli Quality trial plantings in Maine are in the ground and have held up well in the face of changeable conditions this summer. The trial is running at Highmoor Farm in Monmouth, Maine. Transplant dates were June 16, June 27, and July 19.
Rainfall is again an issue this year. From May 14 through August 16, the farm received only 4 inches of rain, about a third of the average amount. Fortunately, soil moisture was very high at the beginning of the season, and each planting has been drip-irrigated twice. Trial leader Mark Hutton reports that the quality of the trial is excellent.
The Quality trial was open for observation during a late July field day at Highmoor Farm. Thirty vegetable growers viewed the plots. The group also included the director of a regional produce distributor interested in expanding the quantity of broccoli procured from small to medium size New England farms.
Evaluations of broccoli in the first planting began on August 1. Many of the entries in that planting are now past maturity. Broccoli in the second planting should be ready for rating from late August through early September. Broccoli in the third planting is expected to produce mature crowns by mid-September.
"Developing an Eastern Broccoli Industry through cultivar development, economically and environmentally sustainable production and delivery" is supported by the Specialty Crop Research Initiative of the USDA National Institute of Food and Agriculture, under Award No. 2016-51181-25402.