Salad, ready to eat from the supermarket.

A crisp, crunchy, lively salad is refreshing, delicious and nutritious, but a salad full of wilted, brown lettuce... not so much. Like a lot of other fresh produce, lettuce has a relatively short shelf life, and it's kind of particular about how it likes to be stored. In fact, lettuce is a little more fragile than a lot of other veggies.

To ensure your salads, sandwiches and other dishes are as enjoyable as possible, it's important that you know how to select the best lettuce and store it, how long to keep it around and how to identify bad lettuce. Proper handling is important too because food poisoning from lettuce is a possibility, especially since it's very rarely cooked.

How to Select Lettuce

There are lots of different types of lettuce, but they can be divvied up broadly into two main categories: head lettuce and loose-leaf lettuce. The former includes varieties that grow in a layered head, like iceberg lettuce, romaine lettuce and Boston and bibb butterhead lettuce. The latter includes varieties that grow on a stalk, like green, red and oak-leaf lettuce.

Whichever type you're buying, and whether it's a whole head, bagged lettuce, a container of salad mix or some other package, choose fresh-looking, nonwilted, vibrantly colored leaves that aren't slimy, browning or dried out by the stem. Also, pay attention to the sell-by, use-by or best-by date on the packaging.

Identifying Bad Lettuce

Lettuce wilts as it begins to go bad, becoming increasingly limp and shriveled. It also turns brown and dries out, starting at the edges and the base of the leaves by the stem. If this is only just starting to occur, you're jonesing for a salad and it's the only lettuce you have, it's still safe to eat. The sacrifice is in quality, as the lettuce will have less flavor and less of a crisp texture.

Generally, though, once lettuce starts to turn like this, it's spoiling and should be discarded. If it's giving off a gross odor or developing a wet or slimy coating, it's definitely time to toss it. Also, if you see black or other dark spots, fuzzy white patches or anything else that may be mold, don't eat any no matter how good the lettuce looks otherwise. Throw out the whole head or package of lettuce.

Lettuce Storage and Shelf Life

All lettuce needs to be refrigerated, as it requires a cold, humid environment. Keep it in the vegetable crisping compartment of your fridge. Packaged lettuce can be stored in its original packaging, while heads should be wrapped loosely in paper towels and put in a sealed container or plastic bag.

How long your lettuce lasts varies a little depending on factors like how fresh it is at the time of purchase and how well it's stored. Typically, loose-leaf lettuce and separated heads hold up for about three to five days. Intact heads stay good a little longer, often around seven to 10 days, though the outermost leaves are likely to start wilting sooner.

Don't freeze lettuce in an attempt to keep it longer. It has too high a moisture content and does not fare well frozen.

A Few Words About Washing Lettuce

There's some debate about whether it's better to wash lettuce before storing it or to wait until you're using it. However, there's no question that it will hold up better in the fridge if it's completely dry while stored. So, if you wash it when you bring it home, use towels or a salad spinner and make sure it's thoroughly dried.

If you go through lettuce quickly and want the convenience of washing and prepping it ahead of time all at once, go for it. Otherwise, feel free to wait and wash it as you use it.

Regardless of when you choose to do it, it is important to wash lettuce before you eat it. Bacteria and dirt stick to it easily. While washing is not as effective as cooking for getting rid of bacteria, it does rinse some away, and it's better than nothing.