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Warning: this popular summer produce may be harmful to your health

July 18, 2020 (Updated: August 3, 2021)
Lily Moran

Summertime is salad time. Leafy greens make perfect meals to protect the summer body you worked on all winter long. And nothing beats the summer heat like a bowl of cool, crunchy greens and other veggies—that is, if they don’t make you sick.

While salads remain the #1 choice for healthy eating, we cannot overlook the potential food safety dangers they present and take important steps to protect ourselves from them.

Top U.S. foods that produce illness

Every year, one in six Americans—some 48 million people—get sick from food. Of those, about 128,000 wind up in hospitals, and 3,000 die.

The guiltiest foods aren’t the eggs, fish and shellfish, meat, and poultry we most frequently suspect are the bad guys.

No. Nearly half of all food-borne illnesses today is caused by produce.

Food TypePercent of Food-Borne Illness, U.S.
Dairy and eggs20 percent
Meat and poultry22 percent
Fish and shellfish6 percent
Produce 50 percent

Source: CDC

A 2013 CDC analysis of food poisoning cases between 1998 and 2008 found that leafy vegetables were responsible for nearly 25 percent of all food poisonings.

That was more than any other food product, including dairy and poultry. And that 1998 percentage has now doubled from 25 to 50 percent.

A prominent food safety expert spells it out.

“Back in the ’90s and early 2000s, E. coli cases linked to hamburgers represented almost all that I did,” said attorney Bill Marler. “Now it’s none of what I do … it’s just salads, raw vegetables.”

So what’s going on here? And why does caution remain the rule?

To understand where we are today, we need to look at the salad food chain, from soil to store to supper.

The trend is in the bag

Let’s face it. Most of us love an easy fix.  The billion-dollar Big Food industry depends on us to prefer their over-processed, over-salted, over-sugared, over-preserved, and fast foods—even at the expense of our health.

Ever alert for a chance to make a buck, Big Food now gives us a rising tide of no-sweat salads.  As the ingredients travel the food supply chain, other parties, often in faraway lands, pre-cut and bag our greens and other veggies for us.

What could possibly go wrong?

Michele Jay-Russell is a food safety researcher at the University of California Davis who has investigated salad-related poisoning outbreaks in the past.  She says the raw vegetables that are the most common food poisoning culprits are basically … wait for it … all salad greens, especially the chopped and bagged kind.

“We really haven’t seen problems with kale and some of the other greens,” she says. “At least not yet.”

But superstar kale might yet have its day, especially if demand keeps skyrocketing. Any raw veggie can be run through the production line.  And the convenience that drives sales of bagged veggies in fact makes them more likely to be dangerous.

It goes like this.

Take a beautiful, fresh head of lettuce. Chop it up.  Add beautiful, fresh carrots, chopped up. Add beautiful, fresh mâche, chopped up.

Give them a rinse (usually, so we’re told) and into a plastic bag they all go. It’s rare for any processing practice to catch and remove 100 percent of the natural bacteria that comes with fresh produce.

And guess what happens in that plastic bag?  Party time for bacteria—moist and protected. It’s a wonder there are so relatively few outbreaks. That’s thanks in good part to another key factor: we eat the vast majority of our foods cooked, which usually eliminates pathogens. But we eat our salads raw, creating a food safety nightmare like the one we lived through only two years ago.

The green scare of 2018

In March 2018, one of the coolest, crunchiest greens was at the center of the largest multi-state E. coli scare in over a decade. A nasty strain of E. coli bacteria attacked people who ate contaminated romaine lettuce. Spread across 36 states, the outbreak led to 210 cases of people falling ill and 5 deaths in Arkansas, California, Minnesota, and New York.

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Among all cases, 96 people, not quite half, were rushed to the hospital, including 20 who developed kidney failure. If the numbers seem small, let’s put them into perspective, where small grows to big.

Remember the number of states affected—36?  And of cases—210? Imagine trying to find the deadly E.coli needle in that haystack of possible sources.

Making it even more complicated, different strains of E.coli appear in a variety of different places, including in our own guts.  We welcome those strains.

But not the strain E. coli O157, responsible for the 2018 outbreak. 

It’s a nasty, virulent piece of work, creating toxins that are dangerous for humans. It’s typically transmitted from animals to humans through animal waste that has contaminated food or water. The symptoms of infection include cramping, vomiting, diarrhea, and, rarely, kidney failure and death.

Fortunately, authorities were able to zero in on the E.coli source (dirty water used to irrigate Yuma, Arizona farms) and declare the outbreak over. But, processed salad dangers like this are far from eradicated.

Who’s to blame?

Big Food sources its raw products from any number of different farms. So it’s terrifically difficult to figure out where contaminated produce comes from.

“When it gets processed, you might have four to five farms supplying the processor on any day,” says attorney Marler. “So was it farmer one, two, three, or four that was contaminated?”

“In a perfect world, nobody would mix and match lettuce so this problem wouldn’t happen,” he said. “I think the [question] is: Is the convenience worth the risk?”

While the big farms and lettuce producers get their act together, the consumers need to ask themselves questions of their own.

Is there still a threat?

For years now, just about the entire medical world has been hammering home the message that whole, raw, local, unprocessed, organic foods are the diet of champions.

Leafy greens and other produce that parties with bacteria in bags are none of the above. And the potential threat of contaminated lettuce isn’t going away anytime soon.

Less than a year after the 2018 romaine lettuce recall, another similar outbreak of the same E.coli strain emerged in California. While no deaths were reported, the 2019 outbreak led to 167 infections across 27 states, 85 hospitalizations, and 15 cases of kidney failure. 

So, when it comes to leafy greens, there’s no such thing being as too careful.

How can we improve food safety?

As we’ve seen, food-borne illness can stem from even the “healthiest” of sources, so we must practice food safety at all costs.

If you absolutely must buy pre-bagged produce, even if it says, “pre-rinsed”, take an extra step of care and give it a good rinse anyway. And make sure to wash your hands before and after handling.

And, if buying and preparing whole foods leaves you with too much of an unused ingredient left over, find creative ways to use it. For example, say, you used half a head of cabbage for coleslaw, think ahead to making cold cabbage borscht later in the week. 

There are plenty of websites, apps, and YouTube videos to get started. You’ll find menu ideas to shop for that prevent wasting that healthy cabbage, or ground meat, or any other ingredient.

And, especially at this time of year, remember that it’s better to be safe than sorry when it comes to proper food handling—especially in summer.

Take good care.


Disclaimer: Please note the date of last review or update on all articles. No content on this site, regardless of date, should ever be used as a substitute for direct medical advice from your doctor or other qualified clinician.

Last Updated: July 18, 2020 
Originally Published: July 26, 2018

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