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Bagged salads are one of the quickest-selling grocery items and range from cut romaine to more diverse greens like arugula to complete salad kits. They've transformed meal prep over the past decade with 83% of U.S. households purchasing them regularly, according to data presented in 2015. Consumers are hooked on the convenience of bagged salads and leafy greens—including myself.
But how do salad kits compare nutrient-wise and food safety-wise to a whole head of lettuce? Are we better off skipping the bagged convenience of pre-washed lettuce and chopped salads? Here's what I discovered when I reviewed the latest research and weighed convenience against nutrient and safety. (Related: The Complete Guide to Leafy Greens (Besides Spinach and Kale!))
Do Bagged Salads Have Fewer Nutrients?
All produce slowly loses nutrients once harvested, so it makes sense that bagged salads may lose even more (compared to a whole head of lettuce harvested at the same time) due to the prep work and packaging that has to occur before they hit grocery shelves.
However, many manufacturers suggest the turnaround time from field to market is usually within a 24-hour period. And while bagged salads do experience more initial loss due to washing and chopping, research suggests they may make up for it when packaged thanks to an oxygen-reducing process called modified atmosphere packaging. Most manufacturers use to this type of packaging to maintain the color of leaves and to extend shelf life, but an added perk for consumers is that lower oxygen levels may also slow the rate at which nutrients like vitamin C and folate are lost. (Related: 5 Brilliant Ways to Get More Nutrients Out of Your Produce)
The thinking seems to be that nutrient loss in bagged salads is comparable, or possibly even less, than a whole head of lettuce stored for the same amount of time. This varies, though, depending on the type of greens, storage conditions, and how quickly they're consumed.
Are Salad Kits Safe to Eat?
Recent E.coli outbreaks meant thousands of recalled bags of romaine lettuce, making some question the safety of bagged salads. The risk for contamination increases the more food is handled, but greens can also get contaminated when coming into contact with other leaves. (Related: What's the Deal with All These Food Recalls? A Food Safety Pro Weighs In)
However, when grown, harvested, and stored properly, the risk of greens having levels of bacteria that can make one sick is pretty low. Also, it's important to realize bacteria are present on all lettuces and greens—whole heads and bagged varieties—but proper storage conditions minimize most risk.
In an interview with NPR, former University of California at Davis food safety expert Trevor Suslow suggested that "detectable contamination in both whole head lettuces and mixed salad greens are very, very low," and that there is little evidence that bagged lettuces are more likely to be contaminated compared to whole heads.
Should You Buy Bagged Salads?
Most of us still don't meet daily vegetable recommendations, but the U.S. is doing better than before—particularly when it comes to leafy green consumption. In fact, the average person ate 22.1lbs of leafy greens in 2014—a huge jump from the 1.4lbs consumed in 1970. There's no doubt that bagged lettuce and greens have played a large role by making it easier and more convenient for consumers to get these leafy greens, and many food safety experts consider this increase in vegetables more important to health than potential risks from bagged salads.
With nutrient loss and bacteria risk comparable to what is seen in whole heads of lettuce and greens, most consider the benefits of increased vegetable consumption—thanks to the help of bagged salads—greater than potential risks. However, there are also a few things that consumers can do to though to get more out of bagged salads and to minimize risks. Here are some tips:
- Store all lettuce and salad greens at 35 to 40 degrees Farenheit
- Buy bagged greens as far away from "use by" date as possible
- Try to eat within a few days of purchase
- Definitely toss if beyond the "use by" date or leaves look slimy
This story originally appeared on CookingLight.com by Carolyn Williams, Ph.D., R.D.