Lettuce, Other Leafy Greens, and Food Safety

"Vegetables are an important part of a healthy, balanced diet. Leafy vegetables (called leafy greens on this page) such as lettuce, spinach, cabbage, kale, and bok choy, provide nutrients that help protect you from heart disease, stroke, and some cancers.

But leafy greens, like other vegetables and fruits, are sometimes contaminated with harmful germs. Washing does not remove all germs because they can stick to the surfaces of leaves and even get inside them. If you eat contaminated raw (uncooked) leafy greens, such as in a salad, you might get sick. To prevent contamination, leafy greens should be grown and handled safely at all steps in the journey from farm to fork.

• CDC estimates that germs on produce that is eaten raw cause a large percentage of U.S. foodborne illnesses (also called food poisoning).
• Leafy greens and other vegetable row crops are a major source of E. coli O157 infections.
• Other harmful germs found on leafy greens include norovirus, Salmonella, Listeria, and Cyclospora.

Although anyone can get food poisoning, these groups are more likely to get sick and to have a more serious illness:

• Adults aged 65 and older
• Children younger than 5 years
• People who have health problems or take medicines that lower the body’s ability to fight germs and sickness (a weakened immune system)
• Pregnant women

Leafy Greens Q&As

Read these Q&As to learn more about how leafy greens get contaminated and how to lower your chance of getting sick from eating leafy greens.

How common are foodborne disease outbreaks linked to leafy greens?

During 2014 to 2018, 51 foodborne disease outbreaks linked to leafy greens (mainly lettuce) were reported to CDC. Five were multistate outbreaks that led CDC to issue warnings to the public. Among those, two outbreaks were linked to packaged salads and two were linked to romaine lettuce. The specific type of leafy greens could not be determined for the other outbreak.

The 1,406 illnesses caused by those 51 outbreaks represent only a small proportion of all illnesses caused by contaminated leafy greens in those years. That’s because most foodborne illnesses are not part of a recognized outbreak. Some outbreaks never lead to consumer warnings because the food is no longer in stores, restaurants, or homes by the time it is identified as the source. Usually the source is not identified, and people might not even suspect that their illness was caused by contaminated food. Also, most outbreaks affect people in only one state, so local or state health departments lead work to identify, investigate, and communicate about those outbreaks.

Most recently, in 2019 and 2020, CDC investigated and issued public warnings on three multistate outbreaks linked to leafy greens..."
Leafy Greens