Beginning in April, 197 people across 35 states contracted E. coli believed to have originated in Yuma, Arizona. Most of the victims reported eating bagged, pre-cut romaine lettuce, although some were merely in close contact with those who became sick from consuming it. Of the 197 victims, 89 required hospitalization. To date, individuals in California, New York, Arkansas and Minnesota have passed away.

In a May 31 blog post by the U.S. Food and Drug Administration (FDA), authors Scott Gottlieb, M.D., and Stephen Ostroff, M.D. noted, “This is a serious and tragic outbreak. And we’re devoting considerable effort to identifying the primary source. We’ve made progress in recent weeks toward this goal. This outbreak of E. coli O157:H7 illnesses is the largest in the United States in more than 10 years.”

That outbreak, which occurred during the summer of 2006, impacted 199 people across 26 states and Canada and included three fatalities. The 2006 incident was ultimately linked to a baby spinach field in California, which had been contaminated by a mix of river water and cattle and feral pig feces. At present, the exact source of the current contamination is still unknown.

In a statement released by the FDA on June 1, they noted, “The traceback investigation indicates that the illnesses associated with this outbreak cannot be explained by a single grower, harvester, processor, or distributor. While traceback continues, the FDA will focus on trying to identify factors that contributed to contamination of romaine across multiple supply chains.”

Across the country, retail food chains and grocery stores responded quickly to the threat. Costco, Walmart and Kroger grocery stores pulled existing lettuce products off their shelves in response to warnings from federal investigators. On April 21, the popular fast casual chain Just Salad took to Twitter to respond to concerns. With nearly 30 locations in the New York and New Jersey area, plus outposts in Philadelphia and Chicago, they reassured customers with the following: “Just Salad suppliers are NOT affected by the possible E.coli outbreak. Our Romaine in all markets is grown in CA, where there have not been any reports of contaminated lettuce. We will be adding Iceberg to the menu for those that would like another lettuce option.”

Selling contaminated food can have significant financial impacts for retailers and restaurants. A Johns Hopkins Bloomberg School of Public Health study published in April 2018 estimated the potential damages to a fast food restaurant due to an outbreak. According to the researchers, a single foodborne illness incident costs between $4,000 and $1.9 million for cases involving fines, lost revenue and legal fees.

In late May, the Arizona Leafy Greens Marketing Agreement, which is administered by the Arizona Department of Agriculture, confirmed romaine lettuce was no longer being produced nor distributed from the Yuma growing region. The last known harvest occurred on April 16, 2018, and – due to the product’s 21-day shelf life – it’s presumed the infected romaine lettuce is no longer available in stores or restaurants.

While the contaminated product is likely out of supply, it remains to be seen whether or not consumer trust in romaine lettuce has been impacted. However, kudos go to the grocers and restaurants who reacted quickly, because it demonstrated effective food safety systems in practice and reinforced consumer trust in their brands.