Cleaning a freshly picked head of lettuce can be an act of mindfulness, your worries melting away as you wash and tear each leaf. And the payoff, along with the beautiful summer salad, is a feeling of virtuous accomplishment.
But if you're a busy working parent, the rip-and-release salad kit in a bag can take some hassle out of dinner prep.
As a culture, it's clear which direction we're headed. Per capita sales of fresh iceberg lettuce have fallen by half over the past 25 years, but there's been a boom in bagged greens and salad kits, sales of which are projected to reach $7 billion a year.
According to the Nielsen Perishables Group, which tracks such things, Americans bought twice as many bags of packaged salads as heads of lettuce last year. And over the past five years, sales of bagged lettuce have been increasing by 6.5 percent every year. Sales of intact lettuce heads have remained flat.
Now, if you're like us, you may have some hesitation about grab-and-go salads. Do bagged greens lose freshness? Are they less nutritious or less safe? Or are these suspicions simply the result of old-fashioned prejudice?
We decided to find some answers.
Let's start with safety. Though you may remember food-borne illness outbreaks linked to bagged greens, the risk is actually quite low, and apparently no higher than from traditional wash-at-home lettuce heads.
Big processors triple wash their greens and have taken aggressive steps to reduce the risk of pathogens on their farms, testing irrigation water and trying to prevent wildlife from entering fields, since birds and rodents can carry disease-causing microbes. Some of these measures were put into place following an E. coli outbreak linked to bagged spinach a decade ago.
Food safety expert Trevor Suslow, from the University of California, Davis, told us in an email that "detectable contamination in both whole head lettuce and mixed salad greens categories are very very low, typically less than 0.1% positives [for pathogen detection]," and that there's little evidence that bagged lettuces carry any more or less pathogen risk compared with heads.
In terms of freshness, it's fair to say that chopping and shredding can lead to browning and wilting.
But large producers — such as Fresh Express, Taylor Farms and Earthbound Farms — process and ship their products to retail grocery chains and food service outlets with pretty impressive efficiency.
"For major supply chains, lettuce and leafy greens are harvested, cooled, and shipped within 24 [hours] or only slightly longer," explains Suslow.
The bagged greens also benefit from a crucial technological innovation, called "modified atmosphere packaging." Essentially, the plastic packaging is engineered in such a way that it "breathes" but also maintains an atmosphere inside the package that will minimize browning and spoilage. Typically, that means a lower level of oxygen, and more carbon dioxide, than the natural atmosphere.
Now, when it comes to nutrition, opinions are easier to come by than facts. Intuitively, it seems there must be something lost in an industrial-scale packaging facility. After all, the greens are typically rinsed in chlorinated water.
But one published study we found concluded that bagged, fresh-cut spinach in those modified-atmosphere packages maintained lots of its nutrients, including concentrations of vitamin C and other beneficial compounds known as flavonoids. The researchers did, however, point to a decline in antioxidants during storage.
Decades ago, head lettuce — widely recognized as iceberg — and Romaine were the most common options. But these two greens are not nearly as nutrient-dense as the mixes of dark, leafy greens that are now widely available — yes, in bags.
Just yesterday, we picked up a $5 clamshell of Earthbound Farm's Herb Blend, which includes varieties of lettuces such as Lolla Rosa and Asian Mizuna that we might otherwise never eat.
The clamshells also pack in arugula, spinach, chard and other dark greens that can serve up a whole day's worth of vitamins A and K in a big salad. (There's also lots of vitamin C, as well as dietary minerals such as magnesium and potassium that we're told to consume more of.)
And here's the kicker. It's reasonable to conclude that the convenience and availability of bagged salad kits has nudged Americans to consume more.
Consider this: Since 1985, our consumption of leaf and Romaine lettuce has more than tripled (from about 3 pounds per person per year, to more than 11 pounds per person), according to data from the U.S. Department of Agriculture.
Considering that eight in 10 Americans don't currently eat the recommended levels of vegetables, this has to be a good thing.
DAVID GREENE, BYLINE: You know, we've been spending a lot of time recently on MORNING EDITION learning about food, and it has created some weird moments. My colleagues Allison Aubrey and Dan Charles have come into the studio at moments and they've brought me things like chocolate cake and bizarrely aged garlic. And we've talked about caffeine and how too much of it could kill you. And now for the first time, we have the two of them together in the studio with me. This is just awesome, you guys. And I'm excited to know what in the world we're talking about now.
ALLISON AUBREY, BYLINE: All right. So today, David, we're going to be talking about salad.
DAN CHARLES, BYLINE: Salad.
AUBREY: Lettuce and...
AUBREY: ...Other leafy greens.
CHARLES: So David, there are basically two kinds of people in the world.
GREENE: OK (laughter).
CHARLES: There are the people who like to get their lettuce as close to the field as possible. They buy the whole head. They wash it at home. They build a salad lovingly.
GREENE: Salad-making is an art.
CHARLES: And then, there are the people who want to just grab a plastic bag off the shelf, take it home, open it and put it in their salad bowl.
GREENE: Ready-made salad, yeah.
CHARLES: Which are you?
GREENE: You know, I think I'm sort of both. I do love sometimes, like, on a weekend, I mean, grabbing all of the produce and sort of putting it together. And I like crisp lettuce and putting the tomatoes...
GREENE: ...And mushrooms and stuff in and shaking it up.
AUBREY: So you've got a foot in both worlds.
GREENE: Yeah, I guess so.
CHARLES: Sitting on the fence.
GREENE: But if I'm really busy - I don't have time - I mean, just grabbing one of those bags and maybe adding a couple extra things can be really easy.
CHARLES: Well, I'll just tell you, America...
CHARLES: ...Is going for the bags.
AUBREY: It's easy. It's convenient. Right? You open this up.
AUBREY: You dump it into a bowl. You know the game, right?
GREENE: Yeah - who has time for making - yeah.
AUBREY: Everything - there's croutons, dressing, and little cheeses. Right?
GREENE: It's great - everything, all you need.
CHARLES: Twenty-five years ago, there was nothing like this.
CHARLES: Now for every one of these heads of lettuce that gets sold, there are two...
GREENE: You're holding just a bare head of lettuce.
CHARLES: ...There are two of these bags sold. They have taken over the market.
AUBREY: Right. These little lettuce kits are a $7 billion dollar market now.
GREENE: That's a lot of money.
AUBREY: That's a lot of money.
GREENE: OK. So we...
CHARLES: And they also come with different things in them. If you notice, here we got one - herb blend. This kind of went hand-in-hand with the rise of packaged salad. Down with iceberg heads, in with baby greens, baby spinach, all kinds of sort of cut little baby sort of salads like...
GREENE: There's, like, spinach mix. There's Italian mix. There's all that stuff.
AUBREY: So all the while people are buying this stuff, they're also kind of looking down on it. There's a bias against this. There's sort of an assumption that this might be a poor substitute.
GREENE: Taking it to the register and being like - I'm so sorry. I just don't have time. This is the only way I can have a salad.
AUBREY: Exactly. I'm going for convenience here.
AUBREY: But I looked into this, and it turns out this does not necessarily translate into a loss of nutrition. So I looked into...
AUBREY: ...A couple published studies. This may be surprising to people. There was a study published in a food chemistry journal. And it actually looked at what happens when you take spinach, put it in a bag - it's in there for about a week. And they found that vitamin C levels were maintained. Flavonoids - those are the little beneficial plant compounds in leafy greens - they were maintained out. Now overall, there was a little bit of a decline in total antioxidants, but this held up pretty well. And I think that is probably a surprise to a lot of people.
GREENE: Yeah, which goes sort of against the grain of what people think about. They think that something that's more packaged, I mean, has to some - there has to be some secret negative thing happening.
CHARLES: You know, we should that there was a technological reason why this is even possible.
GREENE: The packaging.
CHARLES: The packaging. When you tear a piece of lettuce apart, it's going to start to oxidize. It's going to start to break down, start to get...
GREENE: What does oxidize mean? Like, it...
CHARLES: It's like rusting...
CHARLES: ...You know, for a leaf.
AUBREY: It reacts to the oxygen. It turns a little brown.
GREENE: It starts to get ugly and the kind of lettuce you don't want to eat.
CHARLES: But a few decades ago, they came up with this special kind of plastic that breathes, but breathes in a particular kind of way that, you know, extends the shelf life - helps the lettuce sort of maintain its freshness.
GREENE: Really? That bag is breathing?
CHARLES: Yeah. Yeah, it's breathing.
GREENE: Because I feel like when you open it, it's like it pops and the air comes out. And I...
CHARLES: Well, it's breathing a little bit in a controlled way so that it maintains an atmosphere. Typically, you want to have less oxygen in there than in the surrounding environment. And you want to have a little bit more carbon dioxide than in the surrounding environment. And that helps this whole sort of packaged salad thing exist at all.
AUBREY: One thing I should point out here is that all of these bags - another thing that makes this so convenient is you see triple-washed all over these bags. I mean, that's something that really stands out for people. They think aha - triple-washed. This is...
GREENE: What does it mean exactly? I mean, is someone sitting there washing this stuff that's in this bag three times?
CHARLES: A huge factory is washing it three times with, you know...
AUBREY: In some chlorinated water.
GREENE: OK. Why three, not two or four?
CHARLES: Third time's the charm. No, some people have questions about, like - is it safe? Should I wash it?
GREENE: The salads that come in the bag?
CHARLES: The salads that come in the bag versus the head of lettuce off the shelf.
GREENE: Now, you said they're different kinds of people in the world. I'm a kind of person - I will put the bags out in a colander. And I will fully wash.
CHARLES: You will wash it.
GREENE: Yeah, I mean, 100 percent.
CHARLES: Honestly, if you ask the safety experts, they will say - as far as we can tell, there's no difference. You can wash the head of lettuce at home, fine. You can take the bag, and you can wash it if you want. But you really don't have to. You might actually increase the chances of it picking up contamination from other stuff you were preparing in the kitchen.
GREENE: Washing could make it more contaminated?
CHARLES: It can happen.
AUBREY: Well, you might have some contaminants in your sink or on your countertop where you're slicing or washing. And then it could cross-contaminate in your own kitchen...
GREENE: Well, that's news to me.
AUBREY: ...Defeating the purpose of washing it.
CHARLES: But honestly...
GREENE: That's a takeaway.
CHARLES: ...From a safety point of view, you can't really make an argument that one is better than the other.
GREENE: Is there a but here at all, or I can just go all out - hog wild on these bagged salads and...
CHARLES: No. Honestly, our bottom line is the best kind of salad is the one you're going to eat.
AUBREY: I mean, we're living in a country where 8 out of 10 people don't eat the recommend level of vegetables every day. Right? So if you can get a decent salad in a bag and that makes it convenient, you know, go for it. I would say the numbers tell the story here. In 1985, the typical American was eating 3.3 pounds per year of leafy romaine lettuce. That is now up to 11 pounds per year, so a tripling. And I would argue that it's convenience that's driving higher consumption.
GREENE: So we in this country are eating a lot more greens than we used to.
CHARLES: Yeah. I mean, iceberg consumption has come way down over the last 20 years. The consumption of these sort of leaf lettuce and baby greens and all that has gone way up.
AUBREY: Just to put it...
GREENE: And those are more nutritious. I mean, those are the more nutritious ones.
AUBREY: That's right. As a rule of thumb, the darker the green, the more nutrients in there.
GREENE: Allison, you're holding back on us. Dan admitted that he likes making his own salad with fresh ingredients. I said that I'll go one or the other.
GREENE: Where are you on this?
AUBREY: All right. So I have to say I have a foot in both worlds. I've got three kids, as I've told you before. During the week, I got to go with the bag. You know, I dump in the bag. I dump in the cheese. The crouton little packages are still there. This is a kit. I can make a salad in 30 seconds.
AUBREY: On the weekend, I tend to be a little bit more experimental.
GREENE: Dan, you're a parent. How do you find all the time to be so committed to making your own salad?
CHARLES: Listen, if you're committed to something, you find the time, David.
GREENE: All right.
AUBREY: I'm going to come check in on you at dinnertime tomorrow, Dan.
GREENE: Yeah, make us all a salad. We'll be there tomorrow. Thank you so much. All right, Allison Aubrey, Dan Charles, our colleagues who know more about food than anyone I know in the world, talking salad. Thank you both.
AUBREY: Thanks, David.
CHARLES: Thank you, David.
RENEE MONTAGNE, HOST:
Dan and Allison with our colleague David Greene. Transcript provided by NPR, Copyright NPR.