What bacteria commonly cause food poisoning associated with lettuce?

From the Guidelines

The most common bacteria causing food poisoning associated with lettuce are E. coli, Salmonella, and Listeria monocytogenes, with E. coli O157:H7 being particularly concerning due to its potential to cause severe illness. These pathogens can contaminate lettuce through various means, including irrigation with contaminated water, improper handling, or contact with animal waste during growing or processing 1. According to the 2017 Infectious Diseases Society of America clinical practice guidelines for the diagnosis and management of infectious diarrhea, identification of bacterial pathogens is crucial for both clinical management and public health disease control efforts 1.

Key Points to Consider

• E. coli O157:H7 can cause severe illness, including bloody diarrhea and potentially life-threatening hemolytic uremic syndrome 1.
• Salmonella typically causes fever, diarrhea, and abdominal cramps, while Listeria is especially dangerous for pregnant women, older adults, and immunocompromised individuals 1.
• Risk factors for invasive nontyphoidal Salmonella infection include young and advanced age, impaired immunity, and certain medical conditions 1.
• To reduce the risk of food poisoning from lettuce, it is essential to:
  • Thoroughly wash lettuce under running water (no soap needed)
  • Remove damaged outer leaves
  • Keep lettuce refrigerated
  • Follow proper food handling practices, including washing hands and avoiding cross-contamination
  • Consider additional rinsing of pre-washed lettuce as an extra precaution

Important Considerations for High-Risk Groups

• Immunocompromised individuals are more likely to experience severe or prolonged illness from foodborne pathogens, including those associated with lettuce 1.
• Pregnant women, older adults, and young children should take extra precautions to avoid consuming contaminated lettuce due to their increased susceptibility to severe illness 1.

From the Research

Bacteria Causing Food Poisoning Associated with Lettuce

• The bacteria commonly associated with food poisoning from lettuce are:
  • Salmonella spp. 2
  • Escherichia coli O157:H7 2, 3, 4
  • Other enterohemorrhagic E. coli (EHEC) strains 2
  • Enterobacter 5
• These bacteria can be present on the surface of lettuce leaves or internalized within the leaves 5, 3
• The presence of these bacteria on lettuce can pose a significant risk to human health, particularly since lettuce is often consumed raw without thermal treatment to inactivate pathogens 2, 6

Prevalence of Bacteria on Lettuce

• The mean prevalence of Salmonella spp. on lettuce was found to be 0.041 (95% CI: 0.030-0.052) 2
• The mean prevalence of E. coli O157:H7 on lettuce was found to be 0.041 (95% CI: 0.005-0.078) 2
• The prevalence of these bacteria can vary depending on factors such as the country of origin, type of lettuce, and agricultural practices 2, 6

Prevention and Control of Bacterial Contamination

• Adoption of food safety and hygienic practices by lettuce farmers can help reduce the microbial safety risk of lettuce 6
• Novel approaches such as the use of bacteriophage lysins, like PlyEc2, have shown promise in decontaminating lettuce and reducing the risk of foodborne disease 4