Because the physical characteristics of different types of produce vary, the risks of E. coli contamination also vary from one type of fresh produce to the next. Leafy greens, spices, low-growing and tree fruit, and sprouts have all been identified as the source of E. coli outbreaks.
In the case of leafy greens and other produce that grows close to the ground, the following means of E. coli contamination are known:
- Farm equipment can contaminate fresh produce if it comes into direct contact with raw untreated manure, untreated compost, E. coli-contaminated water, animals that shed E. coli in their feces, or with infected workers.
- Water used to irrigate produce can contaminate produce. Runoff should be diverted from fields growing fresh produce and should not be used for irrigation. In addition, E. coli present in flood water deposited on produce fields can contaminate the product before harvest. In 2005, the Food and Drug Administration (FDA) wrote in its “Letter to California Firms that Grow, Pack, Process, or Ship Fresh and Fresh-cut Lettuce/Leafy Greens” (pdf):
- Wild animals such as deer and wild boars that harbor E. coli and other pathogenic bacteria can contaminate fields, especially fields in rural areas next to wetlands or wildlands. Domestic animals and livestock that make their way into fields can also contaminate fresh produce.
- Field workers who are shedding E. coli in their stool can contaminate fresh produce if they do not use proper hand-washing techniques, or if proper toilet facilities are not available to them in the fields where they work.
In October of 2012, Wegmans brand organic spinach and spring mix, sold by State Garden, was the source of an E. coli O157:H7 outbreak among residents of East Coast states. At least 22 New York state residents—mostly in Western New York, were part of the E. coli outbreak. See State Garden Spinach & Spring Mix E. coli Lawsuits & Litigation.
Lettuce sold by Freshway was linked to an E. coli outbreak in April and May of 2010. The CDC counted 26 confirmed and 7 probable E. coli cases in 5 states during the outbreak. E. coli cases were located in Michigan, New York, Ohio, Pennsylvania, and Tennessee. Most cases were college students.
In 2008, an E. coli O157:H7 outbreak that began among students in Michigan spread to include at least 45 residents of Michigan, Illinois, Ohio, and Ontario, Canada. The Michigan Department of Community Health (MDCH) joined with other public health agencies and the Centers for Disease Control and Prevention (CDC) to investigate the outbreak, and quickly learned that industrial-sized packages of iceberg lettuce supplied by Aunt Mid’s Produce Company of Detroit to educational and other institutions was the source of the E. coli outbreak. A trace-back investigation revealed that the E. coli-contaminated iceberg lettuce had been grown in California. See Aunt Mid's Lettuce E. coli Lawsuits.
In 2005 and 2006, Dole brand produce was identified as the source of two E. coliO157:H7 outbreaks. During the 2005 outbreak, at least 23 people in Minneapolis and St. Paul, Minnesota, were confirmed ill with E. coli infections after eating contaminated Dole brand lettuce. Residents of Wisconsin and Oregon also tested positive during the E. coli outbreak, which triggered the FDA to issue a nationwide health alert to warn the public not to eat Dole Classic Romaine, American Blend, and Greener Selection prepackaged lettuce. During the 2006 produce-related outbreak, the FDA and CDC confirmed 205 E. coli illnesses associated with the consumption of E. coli-contaminated Dole brand baby spinach, including thirty-one cases of hemolytic uremic syndrome, 104 hospitalizations, and four deaths. Victims of the E. coli outbreak traced to spinach were identified in 26 states. After the outbreak was over, FDA announced that all spinach implicated in the outbreak had been traced back to a processing facility operated by Natural Selection Foods of San Juan Bautista, California, a company located in the Salinas Valley. A joint traceback by FDA and the State of California revealed that four spinach fields were the possible source of the E. coli contamination. The outbreak strain of E. coli O157:H7 was isolated from cattle fields nearby the implicated spinach fields, as well as from a wild boar that was killed in one of the fields. See Dole and Natural Selections Spinach E. coli Lawsuits.
Sprouts are grown differently from other fresh produce; the temperature, humidity, and available nutrients that promote the sprouting of seeds also promote the growth of E. coli and other pathogens. Alfalfa, clover, and mung bean sprouts have all have been implicated as the source of E. coli outbreaks. Both contaminated sprout seeds and unsanitary conditions at sprouting facilities have been identified as potential sources of E. coli contamination in sprouts.
Raw clover sprouts served on sandwiches at Jimmy John’s restaurants across the Midwest were the source of a 2012 E. coli outbreak. That brought the number of outbreaks traced to sprouts served at Jimmy John’s to 4 in the last 5 years. Two outbreaks wereE. colioutbreaks; 2 were Salmonella outbreaks. See Jimmy John’s Clover Sprouts E. coli Outbreak and Lawsuits
In 2008, an E. coli O157:H7 outbreak was traced to the consumption of food prepared at the Boulder, Colorado, Jimmy John’s restaurant. The Boulder County Public Health Department (BCPH) investigated the outbreak associated with this restaurant, and counted 12 individuals who cultured positive for an indistinguishable strain of E. coli. This number included two employees who became ill with E. coli infections, yet continued to work at the restaurant in a food-handling capacity while symptomatic. Using a cohort study, BCPH determined that the most likely initial source of the E. coliO157:H7 outbreak was sprouts. It is also notable that BCPH inspectors observed improper hand washing during an inspection of the restaurant, which could have contributed to the spread of E. coli from ill employees to restaurant patrons. See Jimmy John’s E. coli Outbreak Lawsuit and Litigation.
Produce that grows on trees
Fruit and vegetable juices can become contaminated with E. colibefore processing. E. coli outbreaks have been traced to fresh apple cider even when steps such as brushing and washing apples have been taken to reduce the opportunity for bacterial contamination. The use of “down” apples, or apples that have fallen to the ground before being harvested, is a risk factor for E. colicontamination since animals – like deer – that shed E. coli can forage for food in orchard areas and fruit can fall in animal feces as it drops from trees. Juice that has been pasteurized or has received other treatment, such as UV irradiation, surface treatment, or high pressure treatment is safe to drink. Juice that has not received such treatment may be contaminated with E. coli or other pathogens.
In November, 2010, apple cider sold by Baugher’s Orchard and Farm of Westminster, Maryland, was the source of an E. coli outbreak. Maryland public health authorities counted at least 7 E. coli infections associated with the consumption of Baugher’s unpasteurized apple cider. See Baugher’s Apple Cider E. coli Outbreak Lawsuit.
Probably the best-knownE. colioutbreak associated with juice occurred in 1996, when Odwalla recalled all juice products that contained unpasteurized apple juice in response to an E. coli O157:H7 outbreak among the company’s customers. A joint investigation between public health agencies from several states, British Columbia, the FDA, and CDC had identified more than 65 individuals who were confirmed ill as part of the outbreak, including more than a dozen children with hemolytic uremic syndrome and one child who died as a result of her E. coli infection. During its investigation into the source of the E. coli outbreak, FDA found numerous violations of health and safety codes at the Odwalla manufacturing plant, including lack of proper sanitizing procedures and poor employee hygiene. The FDA also found that the plant accepted decayed fruit from suppliers. As a direct result of the outbreak, Odwalla began pasteurizing its juices. The outbreak also spurred a response by the federal government, which now requires warning labels to be placed on all unpasteurized fruit and vegetable juice containers. In 1998, Odwalla was indicted and held criminally liable for the 1996 E. coli outbreak. The company pleaded guilty to 16 federal criminal charges and agreed to pay a $1.5 million fine. See Odwalla Apple Juice E. coliOutbreak Lawsuits.