Project Aims To Increase The Safety Of Organic Leafy Greens

A USDA-funded project at the University of Arizona is designed to increase the safety and quality of organic leafy greens and profitability for growers. The endeavor includes outreach and an education program.

The U.S. Department of Agriculture has provided $2.9 million for the University of Arizona to improve the safety and post-harvest quality of field-grown organic leafy greens.

“This is a very comprehensive project covering all aspects of leafy green production, from field to fork,” said principal investigator Sadhana Ravishankar, an assistant professor in the UA’s department of veterinary science and microbiology in the College of Agriculture and Life Sciences.

“The goal is to provide safer and better-quality organic leafy green products for consumers and to increase profitability for growers of organic produce.”

U.S. producers are turning to certified organic farming systems as a way to lower input costs, decrease reliance on nonrenewable resources, capture high-value markets and boost farm income. Since the late 1990s, U.S. organic production has grown steadily. Now, more than two-thirds of U.S. consumers buy organic products at least occasionally, and 28% buy organic products weekly, according to USDA.

Leafy greens include spinach, lettuce, arugula, cabbage and radicchio, all of which are part of the grant in one way or another.

“The large foodborne outbreak affecting mostly organic spinach in 2006 was a reminder of how important it is to ensure safety of leafy greens,” Ravishankar said. “The two most common disease-causing pathogens in leafy greens are Escherichia coli strain O157:H7 and Salmonella enterica. Contamination can come from human or animal excrement, for example from runoff from nearby farms, communities or from contaminated irrigation water.”

While cooking eliminates both E. coli and Salmonella, consuming raw leafy greens can pose a risk.

The researchers are going to look at ways to eliminate bacterial contamination in bagged leafy greens using organic methods. In previous studies, Ravishankar’s team tested edible films made from apples, carrots, or hibiscus, which contained essential oils and other plant extracts. These antimicrobial edible films effectively inactivated E. coli and Salmonella on various foods.

“We are going to test whether these plant extracts and essential oils inactivate bacteria if incorporated into an edible film lining the insides of the bags in which leafy greens are sold or as pieces of edible film mixed into the salad,” she said. “Since the films are made of edible plant parts, they can be consumed as part of the salad.”

“At the field level, we want to look at various production practices as well as environmental factors affecting the quality and safety of leafy greens,” she added. “We will study organic fertilizers, mainly compost teas, and see how the microbes survive in them.”

Those studies will involve growing organic leafy greens on an experimental parcel and fertilizing them with compost teas inoculated with harmless strains of E. coli. The benefits of compost teas and organic nutrients on plant growth will also be evaluated, through Jorge Fonseca at the Yuma Agriculture Center, part of the UA’s College of Agriculture and Life Sciences.

In collaboration with Kelly Bright and Charles Gerba in the UA’s department of soil, water and environmental science, the team plans to monitor irrigation water by sampling water from different areas in Arizona for contamination with E. coli O157:H7, Salmonella and viruses at different times of the year.

“In addition to taking seasonal samples, we are going to sample right after a rainfall to see whether that affects the contamination risk,” she said. “If it turns out that rainfall is causing a hazard, then we’ll advise farmers to not irrigate fields or harvest after rain.”

“Some researchers say the bacteria are only on the surface and there is no way for them to get inside the fruit,” Ravishankar said. “Others say they can. We are going to study how the microbes attach to the plants and whether they get inside. Limited research has been done with regard to these issues in organically grown leafy greens. We hope to be able to find an answer.”

Vegetable surfaces are not the only areas that could breed foodborne bacteria. Contaminated harvesting tools are likely to spread bacteria further.

“Commonly, the growers sanitize the harvesting tool but then use it for harvesting numerous lettuce heads before they sanitize it again,” Ravishankar said. “All it takes is one bad apple in the row for the harvester to spread the microbes to other plants.”

“We will artificially inoculate tools used for harvesting and for coring lettuce with harmless strains of E. coli and put them to the test: How many lettuce heads can they contaminate along the way?”

How effective is washing at removing bacteria from produce? The researchers will take a closer look at that, too. “We will be looking at about a dozen plant extracts, essential oils and organic sanitizers for their effectiveness against bacteria as well as viruses,” Ravishankar said. “The most effective ones can potentially be applied in the rinse water used for washing leafy greens after harvest.”

To ensure that the recommendations are economically viable, the grant includes commercial scale validation of the results. The team plans to assess the efficacy of the most effective organic sanitizers, plant extracts and essential oils by applying them in the flume washers used to clean the harvested produce in Yuma, AZ.

Organic leafy greens treated with the most effective organic sanitizers, plant extracts, essential oils as well as antimicrobial edible films will be evaluated for their sensory acceptability using a panel of consumers.

“We will communicate our results through workshops for people in the industry to make it easy for them to adopt safe practices,” Ravishankar added. “There will be training workshops, field days, presentations to extension agents and media outreach to raise public awareness.” Kurt Nolte, director of Yuma County Extension, will be responsible for this effort.

This grant includes collaborations with scientists from the Southern University Agricultural Research and Extension Center in Baton Rouge, LA, the USDA-ARS-Food Safety Laboratory in Beltsville, MD, and the USDA-ARS-Western Regional Research Center in Albany, CA.

USDA’s National Institute for Food and Agriculture awarded this grant through the Organic Agriculture Research and Extension Initiative.

Source: University of Arizona press release

Leave a Reply

Featured Stories
Greg Lang of Michigan State discusses cherry tree pruning at IFTA 2016.
Fruits
February 8, 2016
Precision Fruit Growing, Business Management Top Agenda At IFTA Conference Kickoff
American Fruit Grower magazine managing editor Christina Herrick posts her updates from the 59th annual gathering. Read More
U.S. Capitol Building FEATURE
Farm Marketing
February 8, 2016
Food Policy: If You Don’t Speak, Others Will Speak For You
British Columbia’s former Minister of Agriculture, Corky Evans, spoke with attendees at 2016 North American Farmers’ Direct Marketing Association’s Convention about Read More
Winery at Krause Berry Farm FEATURE
Farm Marketing
February 8, 2016
How British Columbia And U.S. Regs Are Shaping Farm Markets [Opinion]
Laws passed decades ago to protect small farms aren't keeping up with the realities of modern farmers and their marketing efforts. Restrictions can shut down hosting weddings, but offer incentives to open wineries. Read More
Table with cut flowers at Krause Berry Farm
Farm Marketing
February 8, 2016
3 Tips On How Not To Lose Your Shirt When Adding A Restaurant To Your Farm
Chef and consultant Chuck Currie told NAFDMA Convention attendees the basic principles of what makes a farm market eatery a success or a flop. Read More
field plot
Crop Protection
February 8, 2016
7 Steps To See If Biocontrols Pencil Out For Your Operation
Have you considered adding biocontrols to your operation? If you have, there’s no doubt you’ve already weighed the potential costs, Read More
The family at the helm of Sterman Masser Potato Farms includes (from left) David, Keith, Helen, and Julie.
Photo credit: Rosemary Gordon
Potatoes
February 7, 2016
A Lesson In Marketing From Sterman Masser Potato Farms
Always looking for new product offerings and ways to expand, Sterman Masser Potato Farms caters to consumers. Read More
Thomas Björkman, the director of the Eastern Broccoli Project, discusses details on the challenges of broccoli production in the East.
Vegetables
February 7, 2016
The Eastern Broccoli Project Moves Forward
As acreage increases in the East, mid-sized growers seek channels to distribute their product and continue the search for varieties. Read More
Apples On Display
Fruits
February 6, 2016
Best Research Is Industry Driven [Opinion]
Like many of you, I’m not crazy about a lot of government programs. It’s not that their genesis isn’t noble; God Read More
RosBREED will have an impact on nearly all the major U.S. rosaceous crop production areas.
Fruits
February 6, 2016
RosBREED: A National Effort To Improve The Fruit Industry
The project focuses on improving disease resistance and fruit quality through better genetics and breeding. Read More
The Latest
Fruits
February 8, 2016
Precision Fruit Growing, Business Manage…
American Fruit Grower magazine managing editor Christina Herrick posts her updates from the 59th annual gathering. Read More
Farm Marketing
February 8, 2016
Food Policy: If You Don’t Speak, O…
British Columbia’s former Minister of Agriculture, Corky Evans, spoke with attendees at 2016 North American Farmers’ Direct Marketing Association’s Convention about Read More
Farm Marketing
February 8, 2016
How British Columbia And U.S. Regs Are S…
Laws passed decades ago to protect small farms aren't keeping up with the realities of modern farmers and their marketing efforts. Restrictions can shut down hosting weddings, but offer incentives to open wineries. Read More
Farm Marketing
February 8, 2016
3 Tips On How Not To Lose Your Shirt Whe…
Chef and consultant Chuck Currie told NAFDMA Convention attendees the basic principles of what makes a farm market eatery a success or a flop. Read More
Farm Marketing
February 8, 2016
10 Ideas You Can Steal From NAFDMA’…
We visited several farm markets, as well as poultry and cheese farms and garden shops, this past week. Here are just a few of the best ideas we spied. Read More
Crop Protection
February 8, 2016
7 Steps To See If Biocontrols Pencil Out…
Have you considered adding biocontrols to your operation? If you have, there’s no doubt you’ve already weighed the potential costs, Read More
Potatoes
February 7, 2016
A Lesson In Marketing From Sterman Masse…
Always looking for new product offerings and ways to expand, Sterman Masser Potato Farms caters to consumers. Read More
Vegetables
February 7, 2016
The Eastern Broccoli Project Moves Forwa…
As acreage increases in the East, mid-sized growers seek channels to distribute their product and continue the search for varieties. Read More
Fruits
February 6, 2016
Best Research Is Industry Driven [Opinio…
Like many of you, I’m not crazy about a lot of government programs. It’s not that their genesis isn’t noble; God Read More
Fruits
February 6, 2016
RosBREED: A National Effort To Improve T…
The project focuses on improving disease resistance and fruit quality through better genetics and breeding. Read More
Berries
February 5, 2016
Moving Beyond Methyl Bromide With Biofun…
Editor’s note: University of California Farm Advisor Mark Bolda will present much more information on this topic at the Biocontrols Read More
Grapes
February 5, 2016
Geotextiles Can Help Prevent Winter Grap…
Although Northeast and Midwest grape growing regions have so far been spared from extreme cold this year, the winters of Read More
Grapes
February 5, 2016
Researchers Test New Method To Mitigate …
The use of evaporative cooling in vineyards during hot weather isn’t a new concept, but researchers in Australia are testing Read More
Crop Protection
February 5, 2016
Register Now For Biocontrols Conference …
Space is limited, so register now to attend the first-ever Biocontrols USA 2016 Conference Field and Greenhouse Tour. Following the Read More
Grapes
February 4, 2016
Northern Grapes Project Fuels A Market F…
 There’s a burgeoning market for cold-weather grapes. The Northern Grapes Project, funded in 2011 by a USDA National Institute of Read More
Citrus
February 4, 2016
Can Olive Oil Grease Skids For Florida’s…
Researchers, interested growers help launch new industry. Read More
Citrus
February 3, 2016
Sunkist Expands Organic Portfolio
With the organic citrus sector growing three times as fast as conventional, the 123-year-old cooperative is keeping up with the times. Read More
Citrus
February 3, 2016
Syngenta OKs Buyout By ChemChina
Deal valued at more than $43 billion; Syngenta management team to stay intact. Read More
[gravityform id="62" title="false" description="false"]