Saying it will be one of the most comprehensive studies of fresh produce ever conducted, the University of Maryland Center for Food Safety and Security Systems on Thursday announced an ambitious, $9 million research project to provide scientific guidance on the safest ways to grow, pack, transport and store salad fixings.

“Ever since 2006, when a deadly batch of bagged spinach killed three people and sickened hundreds of others, U.S. farm producers, packers and others along the distribution line have argued over how best to protect consumers,” the UMD researchers said in their announcement.

Now they hope they can settle that fight.

From 1996 to 2007, about 72 reported outbreaks of foodborne illness were linked to 20 fresh produce, both domestic and imported. Tomatoes were implicated in 13 of those outbreaks and leafy greens such as lettuce and spinach were associated with 24 outbreaks.

Leafy greens and tomatoes are the produce items most frequently responsible for foodborne illnesses, “yet we still don’t know what specific safety guidelines are justified scientifically,” said principal investigator Robert Buchanan, the UMD professor  and center director heading the study.

For example, the researchers asked, how far apart does a lettuce patch have to be from pigs or other farm animals to prevent bacterial contamination? What kinds of barriers are needed to prevent contaminated water from reaching crops? What kinds of animal-based fertilizers are safe to use?

While some industry groups have written and attempted to enforce their own standards, Buchanan said this has only served to spark a “firestorm of criticism and complaints” challenging the effectiveness and costs of these efforts.

But there’s a sense of urgency for objective safe practices, especially because the Food and Drug Administration is required by the Food Safety Modernization Act to develop produce safety standards.

To fund the study, the U.S. Department of Agriculture is providing a $5.4 million, three-year grant and produce industry partners are kicking in nearly $4 million in in-kind support. The University of Maryland will be working with Ohio State University, Rutgers University, University of California, Davis; University of Florida, University of Delaware, USDA and the FDA.

In its news release, UMD said agriculture producers are already testing for pathogens in irrigation water, fertilizers and other soil amendments, as well as in produce just before and after harvesting. Some 200,000 separate tests will be analyzed by the researchers. 

The team will conduct a series of controlled experiments by region to gauge how various practices affect levels of pathogens. “Producers, processors and consumers must be assured that the good practice standards apply to their region – that what works on a big farm in California, makes sense on a couple dozen acres on the East Coast,” Buchanan said.

“No group’s protocol will be approved and enforced without scientific validation,” Buchanan added. “The science must be solid enough to withstand domestic legal challenges and international trading disputes.”

He emphasized: “Guidelines, standards and regulations need to be based on solid science or we’ll end up with legal wrangling rather than safer salads.”