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Lettuce: FDA Investigation Summary - Multistate Outbreak of E. coli O157:H7 Illnesses Linked to Ready-to-Eat Salads

Posted December 11, 2013; Updated April 24, 2014

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The U.S. Food and Drug Administration along with the U.S. Department of Agriculture’s Food Safety and Inspection Service, the Centers for Disease Control and Prevention (CDC) and state and local officials investigated a multi-state outbreak of E. coli O157:H7 infections.

What was the Problem and What was Done About It?
The FDA, the U.S. Department of Agriculture’s Food Safety and Inspection Service (FSIS), the Centers for Disease Control and Prevention (CDC), and state and local officials investigated a multi-state outbreak of E coli O157:H7 illnesses linked to ready-to-eat salads.

On December 11, 2013, the CDC reported that the outbreak appeared to be over.  A total of 33 persons infected with the outbreak strain of E. coli O157:H7 were reported from four states: Arizona, California, Texas, and Washington.

On November 10, 2013, the FSIS announced that Atherstone Foods, also doing business as Glass Onion Catering Company, a Richmond, Calif. establishment, was recalling approximately 181,620 pounds of ready-to-eat salads and sandwich wrap products with fully-cooked chicken and ham because some of these products have been linked to the illnesses through epidemiological and traceback investigation.

In a related recall announcement, Atherstone Foods, Inc. of Richmond, Calif. recalled ready-to-eat salads and wraps with “Best Buy” dates 9-23-13 through 11-14-13 because they may be contaminated with E. coli O157:H7 bacteria.  The California Department of Public Health (CDPH) collected salad samples from Atherstone on November 8, 2013; all samples tested negative for E. coli O157:H7. The USDA FSIS collected chicken salad and chicken wrap samples from Atherstone Foods on December 10, 2013 for testing.  These samples tested negative for E. coli O157:H7.

Through a traceback investigation, the FDA and the CDPH evaluated the ingredient list of the recalled salads. Romaine lettuce from a farm in California was the only common ingredient in the salads that was identified during the traceback investigation.  The traceback indicates that romaine lettuce from the farm in California was a likely vehicle for the outbreak.

On November 21, 2013, CDPH collected 10 environmental (soil and water) samples from the harvest field and surrounding areas of the California farm.  Five samples from the surrounding areas of the harvest field tested positive for E. coli O157:H7, although the strain of the E. coli recovered did not match the outbreak strain.

FDA and CDPH investigators observed two cattle operations located near the harvest fields, a possible source of cross contamination.  On December 11, 2013, FDA collected one additional environmental sample, consisting of 25 sub-samples of soil from the California farm and those tested negative for E. coli O157:H7.  Based on the epidemiologic investigation, traceback findings, E. coli O157:H7 positive environmental samples in proximity of a harvest field, and presence of cattle operations, FDA informed the firm of the risks associated with harvesting ready to eat foods such as lettuce from a field in close proximity to cattle operations and will continue working with the firm to ensure measures to control cross contamination are implemented.

Consumers with questions may contact Atherstone Foods at (510) 236-8905 Mon-Fri 9:00 a.m. – 5:00 p.m. PST.

Additional Information for Consumers

Consumers should always practice safe food handling and preparation measures. At home, wash hands, utensils, and surfaces with hot, soapy water before and after handling food; keep raw meat, poultry, and seafood separate from fresh produce and other ready-to-eat foods; cook foods to the proper temperature; and refrigerate perishable foods promptly.   

E. coli is an important cause of human illness in the United States.  Consumers can find more information about E. coli and steps people can take to reduce their risk for infection at the following links:  Food Poisoning - E. coli disclaimer icon
CDC:  CDC E. coli homepage disclaimer icon

Consumers with questions may contact Atherstone Foods at (510) 236-8905 Mon-Fri 9am-5pm PST.

Contact your healthcare provider if you have diarrhea that lasts for more than 3 days, or is accompanied by high fever, blood in the stool, or so much vomiting that you cannot keep liquids down and you pass very little urine.
The FDA encourages consumers with questions about food safety to call 1-888-SAFEFOOD Monday through Friday between 10 a.m. and 4 p.m. Eastern time, or to consult the website:

Additional Information for Industry

The FDA provides guidance, The Guide to Minimize Microbial Food Safety Hazards: The Guide at a Glance, to assist domestic and foreign growers, packers, and shippers of unprocessed or minimally processed (raw) fresh fruits and vegetables by increasing awareness of potential hazards and providing suggestions for practices to minimize these hazards. The guidance will be most effective when used to evaluate individual operations and to institute good agricultural and good manufacturing practices (GAPs and GMPs) appropriate to the individual operations.
In January 2013, the FDA released for public comment its proposed rule to establish science-based standards for growing, harvesting, packing and holding produce on domestic and foreign farms. The rule is one of five proposed rules that would lay the cornerstone for the prevention-based, modern food safety system mandated by the FDA Food Safety Modernization Act. For more information on the Proposed Rule for Produce Safety, please visit FDA’s website.

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