Lettuce is particularly perishable, compared to many other vegetables. You will get a considerably longer storage lifetime if it is refrigerated, rather than kept at room temperature.
The bottom line: Lettuce lasts unrefrigerated for up to 2 hours. If you forget to store your lettuce in the fridge, don't fret. You've got up to 2 hours before you need to throw it out.
Question: How long can salad sit out before it becomes unsafe to eat? Answer: Salads can be safely left out at room temperature for about two hours — or one hour if the temperature is above 90 degrees Fahrenheit.
Bacteria grow rapidly at temperatures between 40° F and 140° F; iceberg lettuce should be discarded if left out for more than 2 hours at room temperature. To maximize the shelf life of iceberg lettuce, refrigerate in a loosely closed plastic bag and do not wash the iceberg lettuce until ready to eat.
Once dried, wrap the lettuce leaves in a paper towel before placing in a plastic bag (the paper towel helps absorb any extra moisture, so your leaves stay crisp). Then, store the plastic bag in the crisper drawer of the refrigerator. These loose lettuce leaves should be consumed within three days of storing.
Lettuce may bolt in response to the stress of high temperatures, and the leaves may become bitter as the plant puts its growth into flowering (see photo at right). Leaves wilt, toughen, and get bitter if the plant becomes water stressed in heat.
You can wash your lettuce before or after storing it in the refrigerator. If you wash the lettuce before storage, place a paper towel in the plastic bag or reusable container, which can absorb excess moisture, preventing your lettuce from turning soggy and extending the shelf life.
Place your salad greens in an airtight container.
We enlisted the University of Otago to test the best storage methods for bagged lettuce. It found that storing them in an airtight container can keep them fresher for longer.
Shelf Life Tips
Bacteria grow rapidly at temperatures between 40 °F and 140 °F; an unopened bag of prewashed salad mix should be discarded if left out for more than 2 hours at room temperature.
Whole heads of lettuce will stay fresher much longer than chopped pieces or individual leaves. From there, the best way to store heads of lettuce is to first remove any damaged or wilted outer leaves, then wrap in a few paper towels.
They Use Perforated Container
The use of perforated bins is the key to keeping lettuce fresh and crisp at all times. Restaurants keep them in perforated containers to allow air circulation in the refrigerator. To keep its crispness, lettuce requires air and a small amount of moisture.
In a word, no. According to James Rogers, Ph. D., director of Food Safety and Research at Consumer Reports, if E. coli (or any other type of bacteria that can cause food poisoning) is present in your produce, washing it won't remove all of those organisms.
Instead of leaving your lettuce in the bag it comes in, wrap each individual head in a piece of aluminum foil and store it in your fridge. Just be sure to wrap it back up tightly every time you use it because any exposed lettuce can dry out quicker.
Yes, it can sit out not more than two hours, but the ingredient you include in your salad may increase or decrease the time. If you have leafy green vegetables like spinach, kale, lettuce, and something like that, you can no longer sit out time for your favorite salad.
Lettuce may cope with light freezing and even one or two hard freezes, but once the thermometer reads 25°F or below, the plants are in danger.
Is It Better to Store Lettuce Washed or Unwashed? Head lettuce, such as iceberg and romaine, keeps fresh longer when it remains attached to the head and unwashed. Rinse the leaves only when you are ready to use them.
First, layer the bottom of the container with paper towels. They'll absorb moisture. Then, gently pack the leaves in the container and top with another paper towel before storing in the crisper drawer. Don't pack the leaves too tightly, or they won't have breathing room (that can invite rapid rot).
In the United States, fresh, commercially produced eggs need to be refrigerated to minimize your risk of food poisoning. However, in many countries in Europe and around the world, it's fine to keep eggs at room temperature for a few weeks.
Ripe tomatoes should still be kept at on your counter, uncovered, if you are going to enjoy the tomato in the next day or two. But any longer than that – the recommendation is to refrigerate. A so-so tomato is much better than a rotten, moldy tomato. Refrigeration will slow down the decay.
Loose leaf lettuce can last seven to ten days when properly stored, but head lettuce lasts much longer than that. Left intact and unwashed, head lettuce will last one to three weeks in the fridge. In comparison to other leafy greens, though, lettuce reigns as the long shelf life champion.