E. Coli Outbreak in Romaine Lettuce: What You Should Know

May 2, 2018 Update
Both the FDA and CDC published updates on the pathogenic E. coli outbreak today. Sadly, one death was reported. This blog post was published earlier in the day and has been updated below the original post.

Romaine Recall: What You Should Know

There is an outbreak of pathogenic E. coli in the US. The Centers for Disease Control and Prevention (CDC) through PulseNet, a national database, recognized the outbreak in March 2018 with the initial CDC announcement on April 10, 2018. With the initial announcement, there were 17 cases across seven states with the largest number identified by the New Jersey Department of Health.

What do we know about the outbreak?

    • The pathogen is Shiga toxin-producing Escherichia coli O157:H7.
    • The likely source is Romaine lettuce.
    • The Romaine lettuce is from the Yuma, AZ growing region.
    • Illnesses started March 13th, 2018.
    • 22 states.
    • 98 cases ranging in age 1-88.
    • 46 hospitalizations, including.
    • 10 patients with hemolytic uremic syndrome, a form of kidney failure.
    • 0 deaths reported.
    • 65% of cases are females.
    • Dozens of farms in the Yuma, AZ region are being investigated.

How do we know what we know?

    • When a clinical isolate from a patient is identified as E. coli O157:H7, the result is reported to the state department of health. The state reports the result to the CDC. The isolate is tested by pulsed field gel electrophoresis (PFGE) and the data are entered in the national PulseNet database. The CDC monitors the database and sees the matches across multiple states. There are differences in strains of E. coli O157:H7, and PFGE is used to show matches of the same strain. The outbreaks isolates are also tested by whole genome sequencing (WGS), a method to fingerprint the strains.
    • Health departments conduct food surveys of patients to learn foods eaten. For this outbreak, 64 of 67 patients interviewed reported eating Romaine the week before the illness started.
    • The Yuma, AZ growing region provides Romaine to the US during the winter growing months.
    • The CDC epi curve shows the first case had an illness start date of March 13th.
    • The CDC Case Count Map shows the number of cases per state.
    E. coli O157:H7 was traced back and found from one farm in Yuma, AZ, after cases developed at a correctional facility in Alaska where whole-head Romaine was shipped. This one farm has not been called the sole source of the outbreak, and the investigation continues in the Yuma, AZ growing region

What do we expect?

    • Illnesses started after April 7th may not be reported yet, so the number of cases will increase. The timeline for the illness and outbreak is:

      1. Onset time is 1-8 days.
      2. Duration of the illness is 5-10 days.
      3. Medical diagnosis can be 2-3 weeks.
      4. PFGE and WGS conducted.

    • Watch for another CDC update on the number of cases and hospitalizations.
    • The investigators will locate the source of E. coli O157:H7. The isolates will be tested by PFGE and WGS. The results from the source will be compared to the patient isolates to detect matches.
    • The number of cases will taper off and the outbreak will be over, due to the end of the Romaine growing season in Yuma, AZ.

What can you as a consumer do?

    • Do not eat Romaine from Yuma, AZ or if the growing location is unknown.
    • Do not eat salad blends containing Romaine, if the growing location is unknown.
    • Do not eat salads, if you do not know if the salad contains Romaine.
    • As we start the summer season, follow the rules of clean, chill, cook and combat cross-contamination.
    • Finally, my favorite rule is, “When in doubt, throw it out.”

Updated information from the CDC and FDA, May 2, 2018

    • The last reported illness started on April 21, 2018.
    • The number of states has increased to 25.
    • The number of cases has increased to 121.
    • The number of hospitalizations has increased to 52.
    • The number of patients with hemolytic uremic syndrome is 14, up from 10.
    • California reported one death.
    • CDC investigations are ongoing.
    • As expected, the growing season is over for the Yuma growing region as reported by the Arizona Leafy Greens Marketing Agreement on April 27, however, Romaine has a 21-day shelf life which puts Romaine with consumers until mid-May or longer.

Because of the timeline for illness and outbreak detailed above, additional cases are expected. I want to note that growers who participate in the Arizona Leafy Greens Marketing Agreement implement strict procedures for food safety. The grower who sourced to Alaska is an active participant in the Agreement and highly regarded for compliance in food safety. Participants must have a food safety plan, employee training in food safety, pass an audit and pass inspections. I hope that the source of the contamination is discovered, and the growers will come back even better than they already were. Food safety is not competitive, and we are all in this together.

Correction: The original blog stated that E. coli O157:H7 was found from one farm in Yuma, AZ. That is not correct as the FDA continues to investigate the source of the pathogen along the supply chain. FDA traced the source of the Romaine shipped to Alaska back to one farm in Yuma, AZ.

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About the Author
Kathy Knutson, Ph.D.
Kathy Knutson Food Safety Consulting
Dr. Kathy Knutson works nationwide with food manufacturers on recall investigations, problem-solving, training, and Food and Drug Administration (FDA) compliance. After being trained in 2016 as a Lead Instructor with the FDA-recognized curriculum for Preventive Controls Qualified Individuals, she delivered over 20 workshops to industry. With over 35 years in microbiology and 15 years of full-time teaching, Dr. Knutson is passionate about training and is an effective communicator at all levels in an organization. She has taught and consulted with companies on laboratory methods, interpretation of lab results, quality assurance, sanitation, environmental monitoring, Standard Operating Procedures (SOPs), Good Manufacturing Practices (GMPs), Hazard Analysis and Critical Control Points (HACCP) and the FDA’s Food Safety Modernization Act (FSMA). As a life-long learner, Dr. Knutson is trained in prevention of intentional adulteration, a topic on the horizon for the food industry. Dr. Knutson is a contributing author at CannabisIndustryJournal.com. Dr. Knutson writes a food safety blog and contributes expert services to manufacturers through connectfood.com, an online site for writing HACCP and food safety plans. When Dr. Knutson is not traveling, she works from home in Green Bay, Wisconsin, where she lives with her husband, two sons, and an adorable Bernedoodle. Learn more about her at https://www.linkedin.com/in/kathyknutsonphd