Following last year’s widespread E.coli O157 outbreak involving romaine lettuce linked to the Yuma, Arizona growing region (Spring 2018), FDA launched a sampling assignment to test romaine lettuce for pathogenic Shiga toxin-producing Escherichia coli (STEC) and Salmonella spp. The microbiological surveillance sampling began on December 18, 2018 in the Yuma region and focused on 26 commercial coolers and cold storage facilities to allow FDA to sample multiple farms from several locations at once. The agency collected and tested a total of 188 samples for both pathogens. It did not detect Salmonella in any sample; STEC was detected in one sample, but additional analysis found that the bacteria was not pathogenic.

“The findings of this assignment suggest that there was no widespread Salmonella or STEC contamination of romaine lettuce from the Yuma growing region during the period when sampling occurred. As a next step, the FDA is working with leafy green stakeholders in the Yuma region to consider a longer-term environmental study to identify and control risks that will prevent future outbreaks, with the ultimate goal of protecting consumers. – FDA

The point of the sampling assignment was to determine whether target pathogens were present, and if so, to respond quickly before contaminated products reached consumers.