HOME > Chowhound > General Topics >


Why do you wash lettuce?

As I was spinning my washed lettuce for a lunchtime salad, it occurred to me that washing lettuce is probably only truly useful if there is dirt or sand in the lettuce. I was washing some mesclun salad that was really clean. I know that you're supposed to wash lettuce in case anyone carrying an illness might have touched it along the food chain, but is washing lettuce in cold water really going to kill anything that might be on the lettuce? Aside from if the lettuce is actually dirty, does washing lettuce do anything except make you feel better? So take a cabbage that you're tuning into slaw, for example-- you remove the outer leaves and then you shred it, so why would you wash iceburg lettuce that you've removed the outer leaves from? Or lettuces that are grown hydroponically? I would really like to know if there is any scientific evidence that this is worthwhile, or is it just a big waste of time?

  1. Click to Upload a photo (10 MB limit)
  1. You are rinsing off at least some of the residual pesticide left on the leaves (could be improved by adding some citric acid/lemon salt--which is the main ingredient in fruit and vegetable washes); also the flouride and other chemicals in tap water do a little to help with cleaning off other yuck:

    "In fact, the FDA says that all fruits and vegetables, including those that are organically grown, could benefit from a thorough washing to remove soil, surface microbes, and some pesticides."
    "To remove exterior bacteria, all you need to do is rub your produce under running water with your hands."

    Regarding hydroponics, they still may be sprayed with pesticides, unless they're the special Mickey Mouse pumpkins which are in forms.

    1. A great question, I have often wondered same. Let's see how long it takes to get an educated answer.

      2 Replies
        1. re: Whosyerkitty

          I have to say, after 30 years of laughing at some of the advice, my mom has proved to be sacrily prescient. So I laugh derisively no longer, though I still go out with wet hair.

      1. No good reason, but I wash all lettuce, however, I've wondered about the inner part of iceberg. After removing the top 1/4 leaves, just how much junk can get into the tightly packed head of iceberg?

        1. Vegetables grow in dirt. They get handled by humans who may not have washed their hands. Some brands for some sorts of greens or veggies claim they have washed before bagging, so they're clean to eat.

          If you think it's clean and hasn't been mishandled, don't bother washing it. There are things I buy at the local farmer's market I don't bother to wash. Bags of greens that say they've been washed then bagged, I don't usually wash those. Other stuff I wash off. I don't like grit in my teeth and the thought of someone's poopy hand on my food is ewgie (I continue to be disturbed by how many people don't wash their hands after going to the bathroom). ;D What's odd about this is I'm not really germphobic at all. I've just seen too many people sneezing on uncovered produce in the supermarket to be comfortable not washing it off first. :)

          1 Reply
          1. re: Morganna

            I don't usually buy the bagged lettuce mixes, but I'd still wash it. Weren't there some cases of illnesses due to e. coli in the bags a few years ago? Or would that make a difference.

          2. Washing and sometimes scrubbing fruit and veggies cleans away most pesticides, soil (produce grows in soil not dirt), and surface microbes. There are residual batcteria from irrigation systems which splash up on things that grow close to the ground. However, if I have a tight, fresh head of lettuce for instance, I take away the outside leaves then use the rest as is. I do the same for cabbage.... for all else I wash and dry. It just makes such sense to take some precautions, especially if one has a compromised immune system or is cooking for small children.

            1. If you've ever had a caterpillar crawl out from under a leaf on your plate, you wouldn't need to ask that question. Yeah, it's just a little extra protein, but I prefer my meat dead.

              10 Replies
              1. re: alanbarnes

                But I am not talking about dirt and bugs, which I would certainly want to wash away. I just want to know if washing lettuce in cold water is getting rid of any food bourn pathogens. Obviously, you can't wash lettuce in anything BUT cold water, so that is what prompted my question. I have the lettuce in the spinner basket of the the lettuce dryer, and I am spraying water on the lettuce until it is throughly doused. Then I am spinning it dry. Is this a worthwhile activity absent the presence of dirt, sand or creepy crawlies?

                1. re: roxlet

                  Well, sure. The force of the water alone would wash away some bacteria.

                  1. re: roxlet

                    I rinse my greens. It certainly doesn't hurt it and it's just as quick to rinse and dry it as to inspect it for dirt & livestock to see if needs rinsing and drying.

                    Removing pathogens is a different matter and rinsing may be worthless. There is growing recognition of the ubiquity and biologic importance of biofilms. Basically a biofilm constitutes a bacterial community bound together by an extracellular matrix. Biofilms are very often strongly adhered to surfaces, either living or inert, such as fruits and vegetables, your skin or teeth (think plaque). It is now recognized that the formation of biofilms may play an important role in many infectious diseases. These biofilms are not removed by rinsing, or soaking or even scrubbing; they may also protect the community from disinfectants such as bleach.

                    1. re: roxlet

                      did you see the FDA rec in my post (the first one)?

                      1. re: Caralien

                        Yes, sorry, I just read that -- the NPR piece? I have a fairly high-powered spray in my sink that I use for rinsing lettuce and other things, so I guess that, at the end of the day, I should keep doing that. But I really wonder about iceburg where you remove the outer layers as you do with cabbage. Anyway, I will continue to wash...

                      2. re: roxlet

                        Sorry to disagree... but lettuce can be washed in warm water with no ill effect. Much as you would prepare flowers for your tableside centerpiece. Very cold water is not recommended for fragile leafy vegetation.

                        1. re: Gio

                          Not recommended by who? Ice water is a great way to refresh lettuce and other leafy greens and herbs. Room temperature water will not likely cause any harm at all. Warm water could easily start wilting many kinds of greens.

                        2. re: roxlet

                          During the most recent e coli in lettuce episode, the CDC informed the American public that this particular bacterium is "sticky." Rinsing doesn't do a bit of good.

                        3. re: alanbarnes

                          Washing gets rid of pesticide residues - most common pesticides of vegetables being water soluble. I wouldn't have to wash if a caterpiller crawled out - a sign of no pesticides.

                          1. re: Sam Fujisaka

                            >>> I wouldn't have to wash if a caterpiller crawled out

                            Yeah, but in that case I'd want to wash in case there was residual catepeller droppings. Also, who knows where all those feet were.

                        4. A number of years ago there was an outbreak of salmonella poisoning in a city south of where i live. It was not confined to one restaurant but several and some people died. The source was finally traced back to the west coast were the lettuce was grown. There were no toilet facilities for the pickers.

                          On another occasion i was picking over and getting ready to wash bagged salad mix. The label said it was prewashed, I turned over a leaf and found a squashed fly. I contacted the company immediately. Their response was to send me coupons for more of the product, freee. No thanks.

                          I wash and pick over my greens and raw vegetables.

                          1 Reply
                          1. re: Candy

                            But the questions remains, would washing the lettuce in cold water have prevented the illness from salmonella. Out of several restaurants, surely at least one washed the lettuce and people still got sick.

                          2. I’ve wondered the same thing. I wash everything anyway, just as a precaution. I guess it makes me feel better about what I’m eating. I’m the same way with canned goods, washing the lid before opening it; or not eating anything that has fallen onto the floor. My father was a microbiologist and was always talking about microbes and “bugs”. Washing produce was something we always did.

                            3 Replies
                            1. re: cuccubear

                              I just read an article about how being overly sanitary can actually be bad for you. Here's the link:
                              I guess that this was what got me think about all of this.

                              1. re: roxlet

                                I believe it. I've heard of these findings before, and it seems logical that our immune systems function better and become stronger when they have something to fight, so to speak.

                                Like I said, I wash my food, but I don't scrub it. And, I'm under no misconception that rinsing my produce will sanitize it . I figure I'll get my share of "whatever is out there" because I don't prepare all my own food anyway. Ultimately I guess, for me, it comes down to what I'm comfortable with. :-)

                                1. re: roxlet

                                  Caralien's link above is a bit more specific than the text she pulled out of it - it notes that these precautions are aimed more towards children, the elderly, and those with compromised immune systems. The risk is minimal but the consequences can be devastating.

                                  The FDA also does NOT recommend using commercial cleaners - water is sufficient so I doubt that rinsing your produce can be considered overly sanitary.

                              2. Washing salad greens in cold water seems to liven and freshen them up a bit.

                                1. water also refreshes the greens so they are crisper

                                  7 Replies
                                  1. re: thew

                                    This is a good point, especially as it relates to lettuce. It is common to rinse the lettuce in cold water and then dry each leaf and wrap them in paper towels and put them in the fridge for a while. Quite labor intensive!!! But it does make the lettuce crisper and better tasting.

                                    1. re: Steve

                                      I'm glad to hear I'm not the only one who goes through this torture. However, I use dish towels in order not to create unnecessary waste

                                      1. re: rworange

                                        Why not use a salad spinner? That's what they're for.

                                        1. re: billieboy

                                          I do. They still don't get the lettuce dry enough.

                                          I hate the whole process of washing lettuce, so I do it once so my lettuce lasts 1 - 2 weeks. To be able to keep that long the lettuce needs to be dry.

                                        2. re: rworange

                                          Right you are, dish towels are an even better idea.

                                          1. re: Steve

                                            Just a note. I don't keep the lettuce in the towels for two weeks. Once the moisture has been absorbed I put it into lettuce keepers or glass jars. Lettuce keepers are just platicware with some holes in it to allow a little air in but not too much. You could take any plastic container and put a nail hole in two sides and it would do it for you,. I also tear it up. For some reason, whole loose leaves don't last as long as torn lettuce.

                                    2. I may not mind worms in my fish or out of date foods, but after living 4 years in Bolivia and then Brazil, I still wash and "sterilize" our fresh vegetables and then air dry them on the dish rack. Cholera and salmonella infestations were found on veggies in Bolivia. We always washed our veggies in the kitchen sink w/ a few drops of iodine and a short cap full of bleach. Considering where much of our fresh produce is shipped from at this time of year, we feel it is prudent. Life of a farm worker in the 3rd world isn't always nice folks. I don't want to eat their "troubles".

                                      2 Replies
                                      1. re: Passadumkeg

                                        I'm with you on this - plenty of rinsing afterwards and I feel safer...

                                        1. re: Passadumkeg

                                          Life of a farm worker here in California is not always nice either. Despite years of attempts to improve working conditions, there aren't always proper toilet facilities in the fields. If iodine and bleach seem like overkill, Trader Joe's sells an inexpensive organic vegetable wash. I have no idea how effective it is, but it makes me feel better.

                                        2. If you have a salad spinner wash the lettyuce and place in the spinner. Take a look at the water that comes off after spinning. You will always wash after seeingthe color. Even the "pre-washed" are dirty.

                                          3 Replies
                                          1. re: jfood

                                            Mine, which was the spring garden mix from Costco, were as clean as a whistle. I have eaten many a salad from a farm stand where the water was definitely dirty and sometimes, very very green. I'm not washing any dirt off of this lettuce. It's strictly "sanitizing."

                                            1. re: roxlet

                                              OK 1 vote for clean batches and 1 vote for numerous dirty batches. You do not want to wash, no biggie to jfood, but he is not eating the dirt he has found in many different batches.

                                            2. re: jfood

                                              I was going to note this very thing! Look at the residue! I do not worry so much once I am deep into a head of romaine or bibb. I look for visual clues. I grow my own, too and it can be just as problematic as anything out of the store but the only thing sneezing on it is the rabbits!
                                              As far as using a salad spinner: I have had better luck getting it to an acceptable level of dryness by spinning and redistributing the leaves and doing it again a time or two. Doing it once usually leaves trapped water.

                                            3. You should worry about the lettuce at the restaurant you eat at if it's being washed properly or if at all.

                                              Years ago managing a restaurant complaints came in from customers finding things like mop string, carton staples, pieces of glass, etc. in their salads. I finally narrowed it down the the new cleaning crew that came in at night. They were using the sink behind the kitchen line to clean and wring out their mops rather than the mop faucet and tub in the trash area. I gave the company hell. I also gave the cooks a scolding because it was stupid on their part for not even looking into the sink to see if there was anything in it before filling it with water and lettuce.

                                              BTW: The sink(s) they use to clean lettuce and food should be cleaned on a daily basis, but other things are washed in those sinks like pots, pans, utensils and peoples hands. Sanitizing?......if it looks clean its clean. Yes, these days there are hand washing stations in newer ktichens, but most the time its more convenient to use the line sink than walk to the hand washing station.

                                              2 Replies
                                              1. re: monku

                                                In my kitchen, we have food sinks, cleaning sinks and mop sinks - as required by DOH. The food sinks would be hugely inconvenient to use incorrectly. And hand sinks are required to be close to every food prep station. Perhaps in old kitchens... Not to mention sanitizing buckets etc.

                                                1. re: Siobhan

                                                  This was a state of the art kitchen meeting all codes at a restaurant that did $2.5 million in sales a year. The food sinks were on the cooks line and mop floor basin in the back trash area.....just laziness and/or unfamiliarity to go and use the correct sinks.

                                              2. Check out my reply t this thread-
                                                So I don't spam the board with al this stuff,
                                                but better safe than sorry.

                                                1. Other people have probably answered, but:

                                                  1) wash off dirt and pesticides
                                                  2) reduce temperature, to "crisp up" the leaves.

                                                  1. One reason is to rinse off the residue of water that was already used to wash the lettuce. This may sound strange, but any water that has been left on it will develop into a nasty sliminess in over several days. Bacteria and whatnot grows in the water that has been left on the lettuce if it has been pre-washed. If you buy pre-washed and bagged greens that were washed several days before you bought them, any residual water can have rather nasty stuff growing in it and it's not worth the risk just to avoid the hassle of washing it again.

                                                    Also, as others have mentioned, it does perk up the lettuce if it's looking a bit lifeless.

                                                    1. jfood is usually not so testy. He often has much to offer regardless of his attitude. There are those of us that want things expressed very clearly and precisely, without ambiguity.
                                                      I think you wanted to know about what might be on lettuce besides dirt (since you are not seeing it on some lettuce), that could be an unseen problem, that could be removed by washing techniques. I think you were continuing to ask for a more sophisticated answer or process, since jfood's and others responses were not what you were hoping for. Some think that when you ask for advice you shouldn't be argumentative. Perhaps your responses were perceived that way. I really didn't get that "tone", myself.

                                                      "is washing lettuce in cold water really going to kill anything that might be on the lettuce?" I would say no. It only washes them off.
                                                      I spray outer leaves as I place them in my salad spinner and then I rinse them in the water, in the bowl several times, till the water is fairly clear. I am really only worried about pesticides and chemicals. I used to play "root the peg" and as anyone who has lost at that will attest, a little dirt never hurt anyone...
                                                      If you like the idea of chemically doctoring the water you soak the leaves in then I see no harm. They certainly treat drinking water with chlorine and iodine has long been a water purifier and disinfectant. Passadumkeg hasn't been adversely affected by doing it other than I think he is growing a second chin. :)

                                                      3 Replies
                                                      1. re: Scargod

                                                        I appreciate your very intelligent and well-considered response.

                                                        1. re: Scargod

                                                          Thanks for theplug S, and jfood apologizes if he came off as testy. Jfood owes you a slice of NH pizza. And it looks like the third and final vote on testiness goes to your side since the mods pulled down his explanation. He was hoping to give Rox some guidance on tone, yet it appears his tone was also not, in line either.

                                                          Oh well at least Rox received the information she desired and has some guidance on washing lettuce versus disinfecting.


                                                          1. re: Scargod

                                                            My mother used to core iceberg lettuce and run water up into the cored base while it was upside down and then drain it for a while before she bagged it. I did the same thing fro a while until I realize that if anything, I was contaminating the inside lettuce with wahtever was in the water or at least I was doing something that was absolutely being stupid

                                                          2. For the many good reasons already spoken of.Plus 1 ? what sort of ??? is in the water that the overhead irrigation system spews with regularity along with the pesticides.Many pond collection systems harbor all sorts of nasty,unhealthy bacteria etc.

                                                            1. In addition to all of the excellent information above, the plastic package that romaine lettuce I buy at Costco in Puerto Vallarta comes in has the instructions "Wash and Rinse" in English and in Spanish "Desinfecte y Lave". So I follow their directions.

                                                              2 Replies
                                                              1. re: mexivilla

                                                                The one thing I hate about that Costco package of romaine lettuce is they purposesly make the package so you can't see the bottom of the romaine to see how brown it is. Otherwise I buy their romaine because it keeps for a couple weeks.

                                                                1. re: monku

                                                                  Sometme you shouldtrim the ends from that romaine and let it sit in a bowl of cold water like it was a bouquet of flowers for a couple of hours. You'll be amazed at how the whole head picks up and goes crispy. It doesn't last as long once it's been refreshed, so do it within a couple of days of using it. Then I wash it- you can or not as y ou see fit.

                                                              2. The Victorian playwright W. S. Gilbert had what may be the first word on this topic. In his operetta "Patience", the poet Bunthorne declaims (with orchestral accompaniment):
                                                                "I do not care for dirty greens By any means."

                                                                1. Is anyone else out there as lazy as I am and use those precut and peeled little carrots?

                                                                  I've been eating them in salads for years and never wash them. As far as I know, I've never had any adverse effects from this. (I do religiously wash and spin dry salad greens.) However, one thing I have noticed about precut carrots is that certain "organic" brands invariably start growing slime only a day or two after the package is opened, while the two or three non-organic brands I've used would never get slimy, even after sitting in the refrigerator with the package opened for a week.

                                                                  4 Replies
                                                                  1. re: racer x

                                                                    Another thing you may notice is that those carrots have almost no carrot flavor. They are for eating cold only, cause at least that way they are crunchy. Try cooking wiith them; they'll be awful.

                                                                    1. re: Steve

                                                                      Actually, while certain brands (and even certain batches within a brand) do lack carrot flavor, there are others that are very good -- carroty and a little sweet. I was surprised to find that the organic brands tend to be especially lacking in flavor.

                                                                      Never cook with them. You're already cutting up other ingredients, so it just takes another few minutes to peel and cut your own carrots.

                                                                    2. re: racer x

                                                                      Uhmm, no. Occasionally used to...
                                                                      After growing carrots I cannot stomach the orange slugs and their slime. I mean no offense, but they might as well be carrot versions of chicken nuggets as far as I am concerned. Reminds me of poop, too, not carrots.

                                                                      1. re: racer x

                                                                        Those "little" carrots are a sham. When they first came out I thought they were like those baby carrots, but the just take regular carrots and grind them down to look like they're "little" baby carrots.