A new publication is available from the Eastern Broccoli project to help eastern growers choose an appropriate cooling system for their broccoli crop. “Cooling Methods for Broccoli: A Guide for Eastern Growers” is available for download at https://extension.tennessee.edu/publications/Documents/PB1904.pdf .

Broccoli must be cooled soon after harvest to preserve nutrients and extend shelf life.  The new publication explains why cooling is particularly important for broccoli compared to other vegetables and provides information on a variety of cooling methods, including slurry icing, hydrocooling, forced air cooling, hydrovac cooling, and others. Additional information is included on food safety, ice, and energy efficiency. Carl Sams led the effort to produce this resource, which was developed with EBP SCRI funding and published by the University of Tennessee.

The USDA Agricultural Research Service (ARS) has released two inbred broccoli lines that are adapted to southeastern US summer environments. Lines USVL156 and USVL160 were developed by Mark Farnham, former broccoli program leader at the US Vegetable Laboratory in Charleston, SC, as part of his efforts with the Eastern Broccoli Project. The releases makes seed of the lines available to any research or commercial program that would like to work with them.

USVL156 and USVL160 stand out for their ability to make high quality, marketable broccoli heads in the heat of a Charleston summer, where the average daytime temperature is 86°F and the average nighttime low is 77°F.  Farnham has tested many commercial broccoli hybrids under these conditions; all failed to produce marketable heads, and some did not produce any heads.

Both lines originated as selections from field-planted, segregating populations. USVL156 was developed through the conventional method of self-pollination to advance the line and generate seed, followed by further field selection. This process was repeated through six generations, then the line was advanced two more generations (to the F₈) through single seed descent.  Inbreeding of USVL160 was achieved through the creation of a doubled haploid line that was selected from summer field plantings and has since been maintained through self-pollinations.

The newly released lines have been used in several hybrid combinations that tested well in Eastern Broccoli trials, even outperforming commercial varieties in the southern Appalachian production region. They are somewhat small in stature and have very early maturity.

More information on USVL156 and USVL160, including how to obtain seed, can be found here or through the link on our Reports page.  Seed is also available for inbred broccoli lines USVL048 and USVL131, which were released from Farnham’s program in 2012.  Additional trial performance data is available from Eastern Broccoli Project director Thomas Björkman.

In the northeastern US, swede midge (Contarinia nasturtii Kieffer) has been an especially troublesome pest for organic and small-scale broccoli producers, many of whom do not have the acreage necessary for the primary management strategy of far (3000 feet) and long (3 year) crop rotations. NEW Crop Rotation Recommendations for Swede Midge, a fact sheet based on research conducted by Cornell Vegetable Extension Specialist and Eastern Broccoli trial leader Christy Hoepting, offers new guidelines for managing the midge on smaller farms.

An understanding of the swede midge life cycle informed Hoepting’s work. Overwintering swede midges can spend up to two winters in larval cocoons in the soil. Adults emerge in spring and early summer in fields that were infested during one or both of the previous two seasons. They live only a few days and are weak fliers. If broccoli or another Brassica is present at the emergence site, female midges will deposit eggs, and the population will increase, with the potential for 4 to 5 generations per season. If no Brassicas are growing nearby to support the next generation, the local population will mostly die off within a few weeks.

Working with several growers in Upstate New York, Hoepting monitored swede midge populations and damage throughout the growing season on each farm. She found that a rotation distance of 500 feet was enough to prevent emerging swede midges from finding the new field, as long as that new field was secluded and separated from previously infested sites by a substantial physical barrier (one that midges can’t easily traverse: woodlots are good, but hedgerows and fences are easily crossed). Likewise, a break of 2.5 to 3 months between Brassica plantings – or delaying the first planting until after mid-July to allow time for spring emergence to subside – disrupted the swede midge life cycle and caused midge numbers to plummet, because they had no place to lay eggs in absence of a host crop.

The success of these strategies depends on a few other key practices that are outlined in the publication. See the fact sheet for further information before implementing the new approach. It can be accessed at the link above, or at https://ecommons.cornell.edu/handle/1813/70145.

As previously reported in this blog, researchers are investigating possible fungicide resistance to the pathogen that causes Alternaria leaf spot and head rot in broccoli. New strains of Alternaria are resistant to commonly used fungicides, so growers should plan their management with current information on effectiveness. To help them with that task, Cornell Vegetable Specialist Christy Hoepting developed a Fungicide “Cheat Sheet” for Alternaria Leaf Spot and Head Rot in Broccoli. It is available for download from the CVP website.  A link is also posted on the Production Resources page of this website.

The “cheat sheet” summarizes products available to New York growers for use against Alternaria, along with rotation restrictions and seasonal maximum use rates. It also provides guidance on how to put together an effective spray program that targets products to appropriate plant growth stages while alternating fungicide classes to avoid resistance. Growers are advised to design a program before the season begins.

Hoepting has first-hand experience with battling Alternaria in her Extension work and in her role as Eastern Broccoli Project Yield trial leader. Her cheat sheet recommendations are based on results of a 2018 trial she conducted to find better management options after previously successful programs failed under high disease pressure. Hoepting is also part of the Control Alt Delete project that is studying the fungus and developing management strategies.

An East Coast-based research group is investigating fungicide resistance in Alternaria, a pathogen that causes head rot in broccoli. Nicknamed “Control Alt Delete”, the project is funded by the Specialty Crops Research Initiative and led by Bhabesh Dutta at the University of Georgia. Collaborators include Eastern Broccoli trial leaders Christy Hoepting and André da Silva, as well as other researchers from Georgia, Virginia, New York, and Nebraska. The project’s website is https://alternariabroccoliproject.uga.edu/welcome/.

Symptoms of Alternaria infection in broccoli often start on leaves, with small dark spots that form concentric rings as they grow. If the infection reaches the broccoli crown, it causes patches of rot that make the head unmarketable. In recent years, fungicides that previously provided control of Alternaria have failed due to the development of resistance, causing economic losses for some growers (see 21 November 2018 post on this blog).

The Control Alt Delete group will study the biology, population structure, and fungicide profile of Alternaria species in eastern production regions and investigate how different production practices, environmental conditions, and sources of inoculum (weeds and seeds) contribute to outbreaks. Ultimately, they will produce a diagnostic tool for Alternaria and develop environmentally and economically sound management programs.

News, information, and research reports from the Control Alt Delete project will be posted on their website as the project progresses.  A link to the that site is also available on the Production Resources page of this one.

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.

Reference

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.

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:

1.  An overview of produce safety
   1. Coverage thresholds and compliance dates
   2. The Food Safety Modernization Act and Produce Safety Rule
2. Broccoli-specific produce safety considerations
3. 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.

(This event has passed.  You can view a recording of the webinar, and download the slides, from Chris Callahan’s blog page here http://blog.uvm.edu/cwcallah/2018/06/18/produce-safety-in-broccoli/ .)