Factors contributing to the contamination of red onions implicated in the summer 2020 outbreak of Salmonella Newport

Between June and October 2020, various agencies investigated a Salmonella Newport foodborne illness outbreak linked to the consumption of red onions supplied by Thomson International of Bakersfield, California. The outbreak caused 1,127 domestic illnesses and 515 reported Canadian cases. It was the largest Salmonella outbreak in over a decade. This outbreak is also significant because the food vehicle, whole red onions, is a raw agricultural commodity that had not been previously associated with a foodborne illness outbreak. The FDA released a report on its findings, including factors that potentially contributed to the Salmonella contamination of red onions. The FDA identified several plausible reasons for contamination that may have contributed to the outbreak. They, including potentially contaminated irrigation water, sheep grazing on adjacent land, signs of animal intrusion including fecal droppings and large flocks of birds that may spread contamination, as well as packing house cleaning and sanitizing practices. A leading hypothesis remained that contaminated irrigation water used in a growing field in Holtville, California, may have led to contamination of the onions. Salmonella isolates from two sediment subsamples and two water subsamples collected during this investigation were genetically related by WGS to clinical isolates from 2016 and 2018 foodborne illness outbreaks (Salmonella Muenchen and Salmonella Montevideo, respectively) associated with the consumption of sprouts. @ https://www.fda.gov/food/foodborne-pathogens/factors-potentially-contributing-contamination-red-onions-implicated-summer-2020-outbreak-salmonella