Shiga Toxin–Producing Escherichia coli (STEC) O157:H7 and Romaine Lettuce: Source Labeling, Prevention, and Business

Abstract

From May to November most romaine lettuce shipments in the United States come from California’s Central Coast region, whereas from December to April most come from the Yuma, Arizona, region. During 2017–2018, the 3 outbreaks of Shiga toxin–producing Escherichia coli (STEC) O157:H7 in US romaine lettuce all occurred at the tail end of a region’s production season. During the fall 2018 outbreak, the US Food and Drug Administration (FDA) recommended that suppliers begin labeling romaine packaging so that consumers can identify the product’s harvest region. We used publicly available data to show that labels may not avert many illnesses in future outbreaks but may reduce suppliers’ financial losses and reduce food loss. Market data available during both 2018 outbreak investigations showed that there was no romaine production from one of the 2 regions when the first illness onset occurred. That is, at the beginning of an outbreak investigation, market data may allow the FDA to quickly rule out an entire production region as a source of contamination.