The CDC, several states, and the FDA are investigating a multistate outbreak of Shiga toxin-producing E. coli O157:H7 infections in 13 states. Seventeen illnesses have been reported from California (3), Connecticut (2), Illinois (1), Indiana (1), Michigan (1), Nebraska (1), New Hampshire (2), New York (1), Ohio (1), Pennsylvania (1), Virginia (1), Vermont (1) and Washington (1). Illnesses started on dates from November 15 through December 8, 2017. Two individuals developed HUS and there has been one death in California.
On December 28, the CDC announced that because the CDC has not identified a source of the infections, CDC is unable to recommend whether U.S. residents should avoid a particular food. This investigation is ongoing, and more information will be released as it becomes available.
In Canada, the Public Health Agency of Canada has identified romaine lettuce as the source of the outbreak in Canada. Currently, there are 41 cases of E. coli O157 illness under investigation in five eastern provinces: Ontario (8), Quebec (14), New Brunswick (5), Nova Scotia (1), and Newfoundland and Labrador (13). Individuals became sick in November and early December 2017. Seventeen individuals have been hospitalized. One individual has died. Individuals who became ill are between the ages of 3 and 85 years of age. The majority of cases (73%) are female.
On December 28, the Public Health Agency of Canada announced that because of the ongoing risk in eastern Canada, the Public Health Agency of Canada is advising individuals in Ontario, Quebec, New Brunswick, Nova Scotia, and Newfoundland and Labrador to consider consuming other types of lettuce, instead of romaine lettuce, until more is known about the outbreak and the cause of contamination.
On January 3, 2018, Food safety experts at Consumer Reports are advising that consumers stop eating romaine lettuce until the cause of the outbreak is identified and that product is removed from store shelves.
I certainly understand that many romaine lettuce growers would like the CDC to call the “outbreak over” because the last onset of illness – thus far in the US – was December 8, and given that lettuce is a perishable product, it is not likely the product is still in stores or restaurants. Generally, I would agree with that, however, because neither Canada or the US has been able to confirm where the contamination occurred – on farm, in processing, in transit – I think I agree with the Canadian and Consumer Reports approach – “When in doubt, throw it out.”
There have been several romaine lettuce related E. coli outbreaks in both Canada and the United Sates in the past decades.
In April 2012, an outbreak of E. coli O157 which sickened 28 was linked to romaine lettuce grown and distributed by Amazing Coachella Inc., which is the parent company of Peter Rabbit Farms, both based in Coachella, California. Health officials in New Brunswick, Canada identified at least 24 people with bloody diarrhea beginning on April 23, 2012. Ill persons lived in the communities of Miramichi, St. John and Bathurst. Most of the patient’s laboratory confirmed with E. coli O157:H7 ate at Jungle Jim’s Restaurant in Miramichi. Food samples collected at Jungle Jim’s were negative for E. coli O157:H7. On June 29, 2012, the Government of New Brunswick issued a press release saying that a case control study involving 18 ill persons and 37 non-ill persons linked illness to consumption of romaine lettuce. The strain found in ill persons in this outbreak was also isolated in persons in Quebec and in at least 9 people California. Most of the California victims ate at a “single unnamed restaurant” according to California public health officials.
In October 2011, an outbreak of E. coli O157:H7 which sickened 58, was first identified in the region around Saint Louis, Missouri. Cases were found in Saint Louis, Jefferson, Saint Charles, and Saint Clair counties and in the city of Saint Louis. The cases ranged in age from 1 to 94. At least six persons were hospitalized. Many of the cases had eaten items from salad bars prior to becoming ill. On October 28, Illinois state health officials revealed that they were investigating an illness that might be linked to the outbreak in Missouri. The link was not described. On October 31, health department officials acknowledged that Schnucks salad bars were a focus of the investigation, however other sources had not been excluded. Cases were identified in Minnesota and Missouri that were linked to college campuses. Additional cases were found in other states; the exposure location in these states was not described. Traceback analysis determined that a common lot of romaine lettuce, from a single farm, was used to supply the Schnucks’ grocery stores and the college campuses. The lettuce was sold to Vaughn Foods, a distributor, that supplied lettuce to the university campus in Missouri, but records were not sufficient to confirm that this lot was sent to this university campus. Preliminary findings of investigation at farm did not identify the source of the contamination.
In May 2010, Cases of a genetically-identical strain of E. coli O145 which sickened 33 were identified in the states of Michigan, Ohio, Tennessee, Pennsylvania, and New York. Illness onsets occurred between April 10 and 26. Several of the cases were students at Ohio State University, the University of Michigan, and Daemen College (Buffalo, New York). Several of the ill in Ann Arbor, Michigan, had eaten at a common restaurant. At least four students in the Wappinger Central School District, in New York State, were also involved in the outbreak. Shredded lettuce served in the school district tested positive for E. coli bacteria. Romaine lettuce was named as the vehicle for this outbreak, on May 6, after the same strain of E. coli O145 was found in a Freshway Foods romaine lettuce sample in New York state. Freshway Foods issued a voluntary recall of various bagged lettuces. The traceback investigation suggested that the source of the lettuce was a farm in Yuma, Arizona. In Ohio, a second, independent strain, of pathogenic E. coli was isolated from Freshway Foods bagged, shredded, romaine lettuce, E. coli O143:H34. This strain was not linked to any known food-borne illness. The isolation of the second strain of E. coli led to an additional recall of lettuce. Andrew Smith Company, of California, launched a recall of lettuce sold to Vaughan Foods and to an unidentified third firm in Massachusetts. Vaughan Foods of Moore, Oklahoma, received romaine lettuce harvested from the same farm in Yuma, Arizona; the romaine lettuce had been distributed to restaurants and food service facilities.
In September, 2009, a cluster of 29 patients who had been infected with an indistinguishable strain of E. coli O157:H7 was identified. Initially case-patients were identified in Colorado, Utah, and New York State. Additional case-patients were identified subsequently in South Dakota, Wisconsin, and North Carolina. The Colorado case-patients had all eaten at the same Chipotle Restaurant in Boulder, Colorado, on September 4, 2009. In Utah, all case-patients had eaten at the Cafe Rio Restaurant located in Salt Lake City, Utah, between August 31 and September 4, 2009. The New York State case patient had eaten at a Chipotle Restaurant. A case control study involving Utah and Colorado case-patients was conducted; it showed that eating romaine, or iceberg, lettuce was associated with risk of illness. The New York State case-patient had eaten romaine lettuce at the Chipotle Restaurant. A traceback of the romaine lettuce led to a common harvester/shipper, Church Brothers, LLC, located in Salinas, California. No lettuce remained for testing and environmental samples collected at Church Brothers, LLC, did not show the presence of E. coli O157:H7. Investigation of the cases in South Dakota, Wisconsin, and North Carolina did not provide useful information for the trace-back investigation. Lettuce was the most likely vehicle for this outbreak because of the common lettuce source for the cases in Utah, Colorado, and New York State. These cases represented 16 out of the 19 confirmed cases. Although Cotija cheese, pinto beans, and pico de gallo consumption were also associated with illness, it was likely that these results reflected confounding as lettuce is usually served with these ingredients in Mexican style restaurants. Cotija cheese was not used in the Colorado and New York Chipotle Restaurants. A common source of cilantro, the most suspect ingredient in pico de gallo, was not identified for Cafe Rio or for the Chipotle Restaurants.
In September 2009, public health officials in Colorado, Minnesota, North Carolina, Iowa, Connecticut, and Missouri identified a cluster of 10 patients with an indistinguishable strain of E. coli O157. The cluster was assigned 0910MLEXH-1. Two Colorado cases ate at Giacomos, a restaurant located in Pueblo, Colorado on the same date, September 6. Cases in Minnesota and Iowa ate at the same restaurant in Omaha, Nebraska. The suspected source of the outbreak was romaine lettuce.
In October 2008, an outbreak of E. coli O157:H7 which sickened 12 was associated with eating at M.T. Bellies Restaurant, Welland, Ontario, Canada. This was one of four, concurrent, restaurant-associated, outbreaks of E. coli O157:H7 that occurred in Ontario, Canada. Romaine lettuce was the suspected outbreak vehicle in this outbreak.
In October 2008, Johnathan’s Family Restaurant in Burlington, Ontario, Canada, was implicated in an outbreak of E. coli O157:H7 which sickened 43 involving romaine lettuce. This outbreak was one of four, concurrent, restaurant-associated outbreaks in Ontario, Canada. The E. coli O157:H7 strain was said to be different from the strain of E. coli O157:H7 outbreak associated with the Harvey’s Restaurant (235 sick) in North Bay, Ontario, the largest of the four outbreaks. The E. coli O157:H7 strain from Johnathan’s was said to be the same as the strain implicated in the restaurant outbreaks occurring at Little Red Rooster (21 sick) and M.T. Bellies Restaurants (12 sick).
In September 2005, genetic fingerprinting test results for an E. coli O157:H7 isolate were posted by the state of Minnesota on the national PulseNet website. Later the state of Minnesota received additional reports of illness among persons who were found to carry the same strain of E. coli O157:H7 bacteria. Epidemiologists, through food histories and a case control study, identified pre-packaged, bag lettuce, produced by the Dole Food Company, Inc., as the likely vehicle of transmission. E. coli O157:H7 was subsequently found in bagged lettuce samples and a public health alert and a FDA recall about the product was issued. Oregon and Wisconsin also found case-patients who had eaten the lettuce. The total number of sickened was 32.
In July 2002, an outbreak of E. coli O157:H7 which sickened 78 occurred among attendees of a dance camp held between July 11-14 on the campus of Eastern Washington University. The camp was for middle and high school girls. Attendees were from Washington, Montana, and Minnesota. Some of the ill girls attended a church camp in Spokane at the conclusion of the dance camp. Secondary cases were subsequently reported at the church camp and also in the girls’ home communities. The cases shared a Pulsed Field Gel Electrophoresis (PFGE), genetic fingerprint, pattern. Case-control study results strongly showed that the Caesar salad, made with Romaine lettuce and served during the July 11 dinner meal and the July 12 lunch, was associated with illness.