Whether it comes thousands of miles from home or from a pot growing on a balcony, lettuce needs to be washed carefully before being eaten. Besides the germs that grow in the soil, bacteria are present that can cause an upset stomach or inflict serious illness from E. coli, staph infections or salmonella. Washing lettuce does not degrade the quality or nutritional content of the food.
Lettuce is an herbaceous plant grouped into five types: leaf lettuce, romaine or cos, stem, crisphead and butterhead. Leaf lettuce includes red and green loose-leaf lettuce, where the leaves form from the base of the stalk, just above the roots. Romaine or cos form tight heads, sometimes sold as hearts of romaine after the tougher outer leaves have been trimmed away. Stem lettuce, also called celtuse, combines the flavor and characteristics of both leaf lettuce and celery. Iceberg lettuce includes crisphead types and is the most common kind sold in markets, and is the most difficult to grow since it is highly sensitive to warm weather. Butterhead forms heads, although not as tight as iceberg, and has a mild flavor and deep green color.
The easiest way to clean leaf, butterhead, romaine or cos, and stem lettuce leaves is to run water over the top and bottom of the leaves once separated from the stems. Some people spin the lettuce leaves dry to remove the excess water or place the leaves on a clean towel that absorbs the water. Iceberg lettuce has a core at the bottom of the head that can be removed by banging it on a counter or hitting it with a sturdy kitchen utensil. Placing the lettuce under a running faucet and forcing the water into the head of lettuce cleans it from the inside out. Tipping it over and placing it on a clean towel drains the remaining water from the lettuce.
Lettuce is palatable raw, eaten in salads, placed on sandwiches, eaten as a garnish or used as a bed to serve food. In some cultures, especially in China, lettuce is an ingredient in cooked food, with romaine topping the list for adaptability since its leaves are sturdier than other kinds of lettuce. Cooking also kills the bacteria or pathogens on lettuce, especially if the temperatures reach 160 degrees Fahrenheit or higher.
The Food and Drug Administration is quick to send out warnings about lettuce after outbreaks of contamination occur. The sources of food-borne illness in raw greens can come from the soil in which the lettuce grows, a handler who has contaminated hands or processing plants. Heeding the FDA warnings is a good idea since E. coli and salmonella can make people seriously ill.