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Lactuca sativa var. longifolia
Also called Garden Lettuce, Lettuce, Cultivated Lettuce
Romaine (cos) lettuce is a variety of garden lettuce that forms tall heads of sturdy, dark green leaves with firm central ribs. It is a cool-season salad crop that, unlike most lettuces, tolerates heat better, and it is best grown fast and kept evenly moist for crisp leaves.
Romaine or cos lettuce (Lactuca sativa L. var. longifolia) is a variety of lettuce that grows in a tall head of sturdy dark green leaves with firm ribs down their centers. Unlike most lettuces, it is tolerant of heat. In North America, romaine is often sold as whole heads or as "hearts" that have had the outer leaves removed and are often packaged together.
Commercially sold romaine lettuce has occasionally been the subject of product warnings by both U.S. and Canadian health authorities warning that consumer supplies can become contaminated with or host pathogenic E. coli bacteria. Cattle can harbor the bacteria without ill effects and be asymptomatic carriers of the bacterium. Lettuce becomes contaminated with the bacterium as the result of cattle manure being used to fertilize crop fields, or the proximity of cattle pastures and feedlots to water sources used to irrigate crops.
From November 2017 to January 2018, the Public Health Agency of Canada (PHA) identified romaine as being linked to illness in 41 persons in Canada. A probably related outbreak affected 25 people in 15 states of the U.S. who ate leafy greens, but the U.S. Centers for Disease Control (CDC) were unable to confirm that it was romaine in particular. There was one death. The disease agent was Shiga toxin-producing E. coli O157:H7. The most recent illness started on December 12, 2017; the PHA declared the outbreak over on January 10, 2018, and the CDC declared it over on January 25.
In response to another E. coli O157:H7 outbreak, which probably began in mid-March 2018, the CDC recommended in April 2018 that consumers not buy or eat romaine lettuce unless they could confirm it was not from the Yuma, Arizona, growing region. On May 22, 2018, after a month-long warning, the CDC announced it was now safe to consume romaine again. The outbreak killed five people and caused 89 hospitalizations across 32 states.
Romaine is a common salad green and is the typical lettuce used in Caesar salad. Romaine lettuce is commonly used in Middle Eastern cuisine. Romaine, like other lettuces, may also be cooked. For example, it can be braised or made into soup. The thick ribs, especially on the older outer leaves, have a milky fluid that gives the romaine its typically bitter herb taste.
Tall blue lettuce · Canada lettuce · Indian lettuce · Willowleaf lettuce · Celtuce · Iceberg lettuce · Lettuce · Prickly lettuce · Bitter lettuce · Lettuce
Text excerpted from the Wikipedia article Romaine lettuce by its contributors, under CC BY-SA 4.0; the excerpts and the care summary drawn from them are shared under the same licence.
The care summary was written by AI (Claude, Anthropic) from the sources on this page, with general growing knowledge where they are silent. Check before relying on it.
