In October 2013, 33 people in four states were sickened by E. coli O157:H7 in an outbreak that was quickly traced back to pre-packaged salads sold at Trader Joe’s grocery locations. On Monday, the California Department of Public Health released its final report on the outbreak with a wealth of new details on the investigation, including two previously unreported additional salad products associated with the outbreak. Early in their investigation, health officials traced the outbreak to two salad products sold at Trader Joe’s: Trader Jose’s Mexicali Salad with Chili Lime Chicken and Trader Joe’s Field Fresh Chopped Salad with Grilled Chicken. Both of those salads were produced by Atherstone Foods Inc., of Richmond, CA, operating under the name Glass Onion Catering. As the investigation progressed, however, health officials identified another two salad products possibly causing illnesses. One of those was another salad product manufactured by Glass Onion and made for Walgreens, while the other was a salad produced by an unnamed company in Oakland, CA. The one common ingredient between all four salads was romaine lettuce shipped by Ratto Bros. of Modesto, CA, and grown by Lake Bottom Farms LLC. Investigators retrieved seven salad samples from the Glass Onion, and all returned negative for E. coli contamination. Similarly, an inspection of the Glass Onion facilities didn’t find any food safety violations or potential instances of cross-contamination. Investigators then went to Ratto Bros. farms to examine procedures and take environmental samples. Out of 44 samples, five taken from the general area, but not upon the premises, tested positive for E. coli O157:H7, but those samples differed genetically from the outbreak strain. Investigators concluded that E. coli contamination may have occurred at the farm from wind transferring pathogens from contaminated areas, or from farm equipment being driven on roads shared with neighboring cattle operations. Ultimately, health investigators could not pinpoint exactly how the salads became contaminated with E. coli O157:H7. Since the inspection, Ratto Bros. has enhanced their procedures in an attempt to avoid any future contaminations. Seven people were hospitalized in the outbreak, including two who developed hemolytic uremic syndrome, a potentially fatal kidney disease associated with severe E. coli infections. The case count by state ended as follows: Arizona (1 illness), California (28), Texas (1) and Washington (3). Food safety law firm Marler Clark was retained to represent two patients in the outbreak. Marler Clark underwrites Food Safety News.