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. It is more nutritious than iceberg lettuce. In North America, romaine is sold as whole heads or as “hearts” that have had the outer leaves removed and are often packaged together.
Origin and etymology
In British English, it is commonly known as “cos” lettuce, and in North America as “romaine” lettuce. Many dictionaries trace the word cos to the name of the Greek island of Cos, from which the lettuce was presumably introduced. Other authorities trace cos to the Arabic word for lettuce, khus خس [xus].
It apparently reached Western Europe via Rome, as in Italian it is called lattuga romana and in French laitue romaine, both meaning “Roman lettuce”. Hence the name “romaine”, the common term in North American English.
Romaine is a common salad green, and is the usual 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, should have a milky fluid that gives the romaine its typically bitter herb taste.
In North American supermarkets, romaine is widely available year-round.
|Nutritional value per 100 g (3.5 oz)|
|Energy||72 kJ (17 kcal)|
|Dietary fibre||2.1 g|
|Vitamin A equiv.||
†Percentages are roughly approximated using US recommendations for adults. |
Source: USDA Nutrient Database
Food safety issues
From November 2017 through 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.
- Walker, Norman Wardhaugh (1970). Cos or Romaine Lettuce Juice. Fresh Vegetable and Fruit Juices: What's Missing in Your Body?. Book Publishing Company. ISBN 9780890190333. Retrieved 2 December 2013.
- Oxford English Dictionary, First Edition, 1893, s.v. 'cos'
- Davidson, Alan (1999). The Oxford Companion to Food. Oxford University Press. ISBN 978-0-19-211579-9.
Cos lettuces are probably not named for the island of Kos but for the Arabic word for lettuce
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- "Public Health Notice – Outbreak of E. coli infections linked to romaine lettuce", Public Health Agency of Canada, February 9, 2018
- "Multistate Outbreak of Shiga toxin-producing Escherichia coli O157:H7 Infections Linked to Leafy Greens (Final Update)", Centers for Disease Control and Prevention, posted January 25, 2018
- "Multistate Outbreak of E. coli O157:H7 Infections Linked to Romaine Lettuce | Investigation Notice: Multistate Outbreak of E. coli O157:H7 Infections April 2018 | E. coli | CDC". www.cdc.gov. 2018-04-20. Retrieved 2018-04-21.
- Sun, Lena H. (2018-04-20). "E. coli outbreak warning expands to all types of romaine lettuce". Washington Post. ISSN 0190-8286. Retrieved 2018-04-21.
- Judkis, Maura (2018-05-22). "Our national romaine lettuce crisis is over, says the CDC. Here's how to celebrate". The Washington Post. Retrieved 2018-05-22.
- Phillips, Kristine (2018-06-02). "Five dead, nearly 200 sick in E. coli outbreak from lettuce. And investigators are stumped". The Washington Post. Retrieved 2018-06-03.
- "FDA Investigating Multistate Outbreak of E. coli O157:H7 Infections Linked to Romaine Lettuce from Yuma Growing Region". FDA. 2018-06-01. Retrieved 2018-06-03.
- Chappell, Bill (June 29, 2018). "It Was The Water, FDA Says Of Romaine E. Coli Outbreak That Killed Five". NPR. Retrieved June 29, 2018.
- Tooke, William (1855). The Monarchy of France: its rise, progress, and fall. London: Sampson Low & Son. p. 634.
- The dictionary definition of romaine at Wiktionary