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Lettuce research, pathogen control pursued on academic, industry fronts



On one hand, leafy greens growers, including romaine growers, are exploring food safety mitigation for lettuce and other greens grown in open fields. On the other hand, the USDA has given $2.7 million to Michigan State University for research into indoor growing techniques.

The two moves are not related, but they touch on the same topic — environmental pathogens and leafy greens.

MSU’s research project on indoor lettuce
A multi-university squad of horticulturists, engineers and agricultural economists are set to work for four years on the study of the indoor production of leafy greens. In addition to the $2.7 million from the federal government the researchers have industry grants bringing the project total to $5.4 million.

Most often consumed raw without a kill step, leafy greens such as lettuce present production challenges outdoors, leading to interest in growing these specialty crops hydroponically in controlled environments, according to a statement from the MSU team. However there is little information on whether this is economically viable.

“Indoor farming, which is also known as vertical farming, using LEDs has a lot of advantages,” according to a statement from Erik Runkle, the MSU horticulture professor who is the official grant recipient.

“It takes much less space, there is more efficient use of water and nutrients, production is year-round, and there are virtually no pesticides. But there is little science-based information about best growing practices, and very little economic data around indoor farming.”

Runkle is collaborating on the project with Roberto Lopez in the MSU Department of Horticulture, Simone Valle de Souza in the MSU Department of Agricultural, Food and Resource Economics, and Chieri Kubota at Ohio State University, Cary Mitchell at Purdue University and Murat Kacira at the University of Arizona.

In addition to data gathering, the researchers plan to encourage indoor farming stakeholders to collaborate with academic and industry groups.

Research is planned to include the review of economic aspects of indoor farming, which involve energy prices that can be cost prohibitive. However, the scientists also are interested in finding out if the quality — in addition to quantity per square foot — of leafy greens will be enhanced by indoor conditions and grow lights. If nutrition, taste, texture or other aspects of leafy greens are improved with indoor growing techniques, the greens would command premium prices.

Growers reviewing options, imposing standards
In an ongoing response to a string of E. coli outbreaks linked to romaine lettuce in the past two years powerful industry groups are on the trail of food safety. Both California and Arizona have organizations called Leafy Greens Marketing Agreements (LGMAs). The organizations say they are unique in the world in terms of certain aspects of food safety.

“As an important reminder, when the LGMA makes changes to our requirements, they are implemented on thousands of farms that produce over 90 percent of the leafy greens grown in the U.S.,” according to a statement released this week by LGMA.

“Government auditors will then verify growers are following the new practices through mandatory government audits. No other food safety program in the world has this capability.”

But those audits aren’t anything without strong standards behind them, and strengthening those standards even more is in the works.

“As public health agencies last week called an end to the latest E. coli outbreaks linked to romaine lettuce from Salinas, (CA), the leafy greens community, government regulators and the entire produce industry continue efforts on multiple fronts to prevent future outbreaks,” the industry groups’ statement says.

The groups imposed stricter standards in spring 2019 in response to outbreaks. New rules for overhead irrigation and setback distances between feedlots and growing fields are two of the biggest changes.

Additional changes are being considered, as recommended by LGMA leadership in December 2019 in the midst of two outbreaks.

“Toward this end, the LGMA has appointed industry experts to serve on a series of new subcommittees to address specific areas involved in the production of leafy greens,” according to the organizations’ statement.

More research into how and why romaine lettuce and other leafy greens are subject to contamination in open growing fields is also in the works via industry and government cooperation. The organizations refer to the work with the Food and Drug Administration as notable.

“We absolutely must know more about why and how our products are being exposed to pathogens in the environment. A few notable projects with support from the U.S. FDA are underway to monitor and collect data in Arizona and California growing regions,” the LGMAs reported. Click here to read more about the LGMA plans.