On September 14, 2006 the U.S. Food and Drug Administration (FDA) released a “Warning on Serious Food borne E. coli O157:H7 Outbreak.” The FDA announced that a multi-state outbreak of E. coli O157:H7 that “may be associated with the consumption of produce.” The FDA stated that, “preliminary epidemiological evidence suggest that bagged fresh spinach may be a possible cause of this outbreak.” As of that date, 50 cases of illness had been reported to the Centers for Disease Control and Prevention (CDC), including 8 cases of HUS and 1 death. The impacted states were noted to include Connecticut, Idaho, Indiana, Michigan, New Mexico, Oregon, Utah and Wisconsin.
In the ensuing three weeks, the FDA issued numerous press releases reporting on the expanding size and scope of the outbreak. The releases also followed the FDA as it zeroed in on its conclusion that the source of the outbreak was Dole bagged spinach.
On September 15, the FDA issues an additional press release advising, “people not eat fresh spinach or fresh spinach containing products.” The FDA indicated that 94 cases of illness, including 14 cases of HUS and 1 death were now associated with the outbreak. The outbreak was identified as affecting 20 states. Concurrently, Natural Selection Foods (NSF) recalled all of its products containing spinach with “use by” dates from August 17, 2006 through October 1, 2006. The recall included Dole brand spinach.
New press releases on September 16, 17, 18, 19 updated the number of illness to 131, including 20 cases of HUS, 66 hospitalizations, and 1 death in 21 states. By this time there were two recalls, including the one initiated by NSF.
The FDA and CDC, in conjunction with local and state health agencies across the country continued its investigation of the outbreak. On September 20, the FDA reported that the New Mexico Department of Health had “linked a sample from a package of spinach with the outbreak strain of E. coli O157:H7.” The package had contained spinach eaten by a New Mexico outbreak member before becoming ill. The package of spinach that tested positive was “Dole Baby Spinach, Best if Used by August 30.” At the same time, the FDA indicated that it had no evidence that frozen spinach, canned spinach, or spinach in pre-made meals manufactured by food companies were affected, and announced those products safe to eat.
The following day, September 21, the FDA confirmed that the genetic testing done on the Dole bag in New Mexico was a match to the strain of E. coli O157 that had sickened what was then a reported 157 people across the country. The list of affected states had grown to 23.
On September 22, the FDA announced that the implicated spinach had all been grown in one or more of three counties in California, Monterey, San Benito, and Santa Clara. The FDA was working with the CDC to further narrow the area of implicated spinach. The outbreak had grown to 166 illnesses in 25 states.
On September 24, the FDA announced further laboratory confirmation of the outbreak. The Utah Department of Health and the Salt Lake Valley Health Department reported that another bag of Dole baby spinach had tested positive for the outbreak strain of E. coli O157:H7. The list of victims on that date included 173 illnesses, 27 cases of HUS, 92 hospitalizations and 1 death.
On September 29, the FDA announced its preliminary conclusions regarding the outbreak. The FDA announced that:
…all spinach implicated in the current outbreak has traced back to Natural Selection Foods LLC of San Juan Bautista, California. This determination is based on epidemiological and laboratory evidence obtained by multiple states and coordinated by the [CDC].
The FDA also updated the number of illnesses, and reported on numerous new laboratory findings of the outbreak strain of E. coli O157:H7 in bags of Dole baby spinach.
Over the ensuing 10 days, the FDA continued to update the number of illnesses, as well as the growing number of Dole baby spinach bags that had tested positive for the outbreak strain of E. coli O157:H7. On October 5, the U.S. Department of Justice issued the following press release:
The US Attorney’s Office for the Northern District of California announced that agents of the FBI and FDA Office of Criminal Investigations executed two search warrants today on Growers Express in Salinas, CA, and Natural Selection Foods in San Juan Batista, CA, in connection with the September 2006 outbreak of E. coli 0157:H7 that the FDA has traced to spinach grown in the Salinas area…United States Attorney Kevin V. Ryan stated that "I want to reassure the public that there is no indication in this investigation that leaf spinach was deliberately or intentionally contaminated. We are investigating allegations that certain spinach growers and distributors may not have taken all necessary or appropriate steps to ensure that their spinach was safe before it was placed into interstate commerce…
On October 12, the FDA reported that test results from the investigation of the outbreak indicated that environmental samples taken from the implicated fields on four ranches had tested positive for the outbreak strain of E. coli O157:H7. According to the FDA, the four fields were located in Monterey and San Benito counties.
The most recent tally from the FDA included 204 illnesses due to E. coli O157:H7 reported the CDC. This number included 31 cases of HUS, 102 hospitalizations, and 3 deaths. The FDA maintained its conclusion that all the implicated spinach was traced back to NSF. The FDA also reported 13 “confirmed product samples that contain the E. coli O157:H7 outbreak strain.” Each of these products was bagged Dole baby spinach.
Read more about E. coli O157:H7 outbreaks at Marler Clark. Read more on prior lettuce and spinach-related E. coli O157:H7 outbreaks, specifically the Dole outbreak of 2005 below:
E. coli O157:H7 outbreaks associated with lettuce or spinach, specifically the "pre-washed" and "ready-to-eat" varieties sold under various brand and trade names, are by no means a new phenomenon. In October 2003, 13 residents of a California retirement center were sickened and 2 died after eating E. coli-contaminated "pre-washed" spinach. In September 2003, nearly 40 patrons of a California restaurant chain became ill after eating salads prepared with bagged, "pre-washed" lettuce. In July 2002, over 50 young women were stricken with E. coli at a dance camp after eating "pre-washed" lettuce, leaving several hospitalized and one with life-long kidney damage. The Center for Science in the Public Interest found that, of 225 food-poisoning outbreaks from 1990 to 1998, nearly 20 percent (55 outbreaks) were linked to fresh fruits, vegetables, or salads.
It is clear that the risks associated with E. coli O157:H7 and lettuce were well known to Dole and the industry prior to the 2005 outbreak. For some time prior to the outbreak, the FDA had been aggressively trying to get the industry to address serious deficiencies that were creating a critical risk to consumers. The response by Dole and many of its industry brethren was woefully inadequate.
In November 2005, the FDA elucidated its past efforts and present concerns in its "Letter to California Firms that Grow, Pack, Process, or Ship Fresh and Fresh-Cut Lettuce." The letter begins:
This letter is intended to make you aware of the Food and Drug Administration’s (FDA’s) serious concern with the continuing outbreaks of food borne illness associated with the consumption of fresh and fresh-cut lettuce and other leafy greens.
The FDA goes on to identify 18 outbreaks of E. coli O157:H7 associated with fresh or fresh-cut lettuce, resulting in 409 illnesses and two deaths since 1995. According to the FDA, completed trace back investigations in eight of the outbreaks “the 2005 Dole outbreak included” were traced to Salinas, California. The FDA further states that the industry’s role in preventing these illnesses is crucial because "these products are commonly consumed in their raw state without processing to reduce or eliminate pathogens."
The FDA efforts to lead the lettuce industry to safer practices were nothing new. In 1998, the FDA issued guidance to the industry entitled "Guide to Minimize Microbial Food Safety Hazards for Fruits and Vegetables." The guide is specifically designed to assist growers and packers in the implementation of safer manufacturing practices. On February 5, 2004, the FDA issued a letter to the lettuce and tomato industries to "make them aware of [FDA's] concerns regarding continuing outbreaks associated with these two commodities and to encourage the industries to review their practices."
The 2005 Dole outbreak prompted even more industry-admonition by the FDA: "In light of continuing outbreaks associated with fresh and fresh-cut lettuce and other leafy greens, particularly from California, we are issuing this second letter to reiterate our concerns and to strongly encourage firms in your industry to review their current operations." This November 2005 FDA letter explicitly rejected industry excuses for not having taken prior action. Further, the FDA cited to research linking some or all of the outbreaks to sewage exposure, animal waste, and other contaminated water sources. The research further indicated that industry practices, including irrigation and field drainage methods, might have led directly to the contamination of the lettuce with E. coli O157:H7. As a result the FDA stated that it considers "adulterated" any ready to eat crops that have come in contact with flood waters. The FDA closed by warning industry members that food produced under unsanitary conditions is adulterated under ß402 (a)(4) of the Food, Drug, and Cosmetic Act, and that enforcement actions would be considered.
The 2005 Dole Outbreak
"DOLE Classic Romaine is triple washed and ready-to-eat. As a result, it is not necessary to wash the salad prior to eating."
On September 22, 2005 the Minnesota Department of Health (MDH) Public Health Laboratory (PHL) received an E. coli O157:H7 isolate for confirmatory testing and Pulse Field Gel Electrophoresis (PFGE) sub typing. PFGE results were reported on September 26 and uploaded to PulseNet, a national database of PFGE patterns or "fingerprints" maintained at the federal Centers for Disease Control and Prevention (CDC). The pattern derived from digestion with the restriction endonuclease Xba I was assigned Pattern number EXHX01.0238. The isolate was soon tested with a second enzyme, Bln I, and the resulting pattern was assigned pattern number EXHA26.1040. Prior to September 19, the Bln I pattern had not been posted on PulseNet.
Isolates obtained from culture of stool submitted by two new ill patients were received at the MDH PHL on September 23, 2005 and subtyped. PFGE results showed that the two new isolates and the isolate received on September 22 were indistinguishable by two enzymes. By September 29, 2005 isolates obtained from seven more patients arrived at the MDH PHL for further analysis. Public health investigators recognized that an E. coli O157:H7 outbreak was underway in Minnesota.
While laboratory testing was performed, MDH epidemiologists conducted preliminary interviews with patients who were laboratory confirmed with E. coli O157:H7. On the morning of September 28 investigators had identified pre-packaged lettuce produced by Dole Food Company, Inc. as the likely vehicle of transmission for infection with E. coli O157:H7. A supplemental questionnaire focusing on the type and brand of lettuce consumed and where it was purchased, was developed and administered to case-patients previously interviewed and newly identified cases. On September 29 Minnesota Department of Agriculture (MDA) staff collected a bag of Dole lettuce at the home of a case patient and began microbiologic testing for the presence of E. coli O157:H7.
On September 30 the MDH issued a press release advising the public that 11 cases of E. coli O157:H7 had been identified in Minnesota residents who had eaten Dole lettuce purchased from at least four different stores in the Twin Cities area. See Attachment No. 2, Minnesota Department of Health News Release, September 30, 2005. Dr. Kirk Smith, an MDH food borne disease specialist, advised consumers to discard Dole pre-packaged lettuce mixes with the "Best if Used by 09/23/05" date. Persons with symptoms of E. coli were told to contact the MDH and their physician. Dr. Chris Braden at the Food borne and Diarrheal Disease Branch at the CDC announced that no other states were reporting outbreak-associated cases.
Meanwhile MDA microbiologists continued to process lettuce specimens obtained from households with cases of confirmed E. coli O157:H7. On Monday, October 3 the agency reported that sample number M-05-2310, Lot Number B250215B received on September 30 had tested positive for E. coli O157:H7. The isolate obtained from the sample was sent to the MDH for PFGE analysis. The resulting pattern was indistinguishable to the pattern identified in case-patients. A second specimen, M-05-2318, lot number unavailable, would also yield positive results.
News of the positive lettuce specimen prompted the Food and Drug Administration (FDA) to issue a nationwide health alert regarding Dole pre-packaged salads on October 2. The FDA announcement reiterated warnings expressed in the MDH press release and further described the Dole products associated with illness, Classic Romaine, American Blend, and Greener Selection. Although cases had only been identified in Minnesota, the product was noted to have been distributed nationwide.
It would not be long before cases of E. coli O157:H7 in Wisconsin and Oregon would be recognized. The Wisconsin case was a 12-year-old female with E. coli O157:H7 who had a history of eating Dole pre-packaged lettuce. PFGE sub typing showed that her isolate was indistinguishable to the EXHX01.0238 pattern and one band different on the second enzyme pattern. Despite the one band difference, MDH molecular epidemiologists considered the girl to be part of the outbreak concluding that the difference was not enough to preclude the case from being considered outbreak related.
The Oregon case was indisputably associated with consumption of Dole pre-packaged salad mix. A 60-year-old Portland resident was hospitalized and laboratory confirmed with E. coli O157:H7 on September 21, 2005. The patient had experienced onset of symptoms on September 18, four days after purchasing and consuming Dole brand "Classic Romaine" salad mix. Michael Roberson, representative for Albertsons’, the grocery store of purchase, confirmed that the chain’s Portland area distributing center had received Dole Greener Selection and Dole Classic Romaine. A portion of the salad mix was still in the patient’s refrigerator. A photograph taken of the packaging documents that Ms. Scheetz purchased Dole salad mix with a "Best if Used By" date of 9/23/05, lot number was B250215B. PFGE sub typing showed that the Oregon isolate was indistinguishable by two enzymes to other ill Dole lettuce consumers in Minnesota.
Aware of the potential severity of an E. coli O157:H7 outbreak, the FDA and the Food and Drug Branch at the California Department of Health Services initiated an investigation at the Dole processing plant. Preliminary information indicated that 22,321 cases of Dole pre-packaged lettuce with a "Best If Used By" date of 9/23/05 and a production code starting with "B250" were shipped from a single Dole processing facility in central California to 34 states in early September. Investigators estimated that since each case contained between 6 and 12 bags, approximately 244,866 bags of lettuce had made it to market.
On October 11, 2005 the MDH counted 23 laboratory confirmed cases of E. coli O157:H7 and seven epidemiologically linked cases. Illness onset dates ranged from September 16 to September 30. Two cases had developed Hemolytic Uremic Syndrome (HUS). Oregon and Wisconsin reported one case each. Case control study data show a statistically significant association between illness and consuming Dole pre-packaged lettuce with a matched odds ratio of 6.8, 95% confidence interval, 1.4-31.9, and a p-value of 0.01.