Posted on 07/29/2025 9:40:59 AM PDT by Red Badger
Contaminated irrigation and inadequate cold storage are fueling E. coli in lettuce. But the fix? It’s simpler—and more effective—than you might think. Credit: Shutterstock Romaine lettuce has been linked to repeated E. coli outbreaks, but new research from Cornell University uncovers how contamination happens—and how to stop it.
The study highlights irrigation water, especially untreated surface water applied through spray systems, as a key culprit. Switching to drip or furrow irrigation and improving cold storage during transport can drastically reduce risk. The research urges a systems-wide rethink, showing how smarter farming and better logistics—from the field to the fridge—can prevent outbreaks and boost food safety.
E. coli in Romaine: A Persistent Threat
E. coli outbreaks linked to romaine lettuce have remained a persistent public health issue. New research from Cornell University highlights that a combination of on-farm strategies and post-harvest handling methods could significantly reduce the risk to consumers.
The study was co-authored by Renata Ivanek, a professor in population medicine and diagnostic sciences, and Martin Wiedmann, a food safety professor. Their findings emphasize practical steps that could meaningfully enhance the safety of romaine lettuce grown and sold in the United States.
Key Risks: Irrigation Water and Contamination
“This study supports that interventions should focus on reducing produce contamination via contaminated irrigation water, on assuring that produce washes applied during processing consistently deliver reasonably high reductions of bacterial numbers, and on improving temperature control during distribution,” Wiedmann said.
“We tried to describe the system as holistically as possible to account for different risk factors and how they could have interactions,” Ivanek said. “There’s not just one intervention that will save us all. We spent a lot of time trying to understand the preharvest component, especially the irrigation water piece, and how much risk can be explained by that.”
Spraying lettuce with untreated water may look routine, but it’s a major contamination risk. Scientists now urge growers to rethink irrigation practices to help prevent future E. coli outbreaks. Credit: Shutterstock
Irrigation Methods Make a Big Difference
The study found that a large portion of contamination stems from the use of untreated surface water delivered through overhead spray irrigation. The researchers observed that switching to treated water or using alternative irrigation systems, such as furrow or drip irrigation, significantly reduced the risk.
“While not the most common system, spray irrigation is used in a number of fields for its benefits during germination, its cooling effect on plants, and other reasons. But drip or furrow irrigation reduces the probability that water directly touches the leaves,” Ivanek said, acknowledging that switching to these other irrigation systems introduces significant potential additional costs to the grower.
The Cold Chain’s Crucial Role
Ivanek and her co-authors also explored the importance of maintaining proper cold storage temperatures along the entire supply chain to romaine’s final destination.
“Time and temperature play a role in food safety, and also in food quality and shelf life,” she said, describing a “perfect storm” if contamination happens at the farm or processing level and then improper transportation temperatures allow bacteria to grow.
The comprehensive practices and interventions explored in this study intend to aid decision-makers in establishing and enhancing food safety best management practices, Ivanek said.
America’s Food Supply: Safe, but There’s Room to Improve
“The big message is the American food supply chain is extremely safe compared to other countries,” she said. “We’re exploring how we can make it even safer and where we should put additional effort.”
Reference:
“Risk assessment of Escherichia coli O157:H7 along the farm-to-fork fresh-cut romaine lettuce supply chain”
by Ece Bulut, Sarah I. Murphy, Laura K. Strawn, Michelle D. Danyluk, Martin Wiedmann and Renata Ivanek, 20 May 2025, Scientific Reports.
DOI: 10.1038/s41598-025-01585-z
Spinach has the same problem as Romaine for being susceptible to E Coli contamination. It’s 2nd on the list for contamination frequency followed by Iceberg.
Cabbage and Leaf Lettuce have the lowest rates. And Kale, but who eats that crap.
I like a mix of red cabbage and red leaf.
Apparently lots of it..................Messycans........
And they still grow it in shitty water......
I have a couple of those indoor hydroponic systems that keeps me with lettuce. Store bought lettuce turns my stomach. I use to live in the central valley of California. Just look at the water flowing through the canals they use to irrigate ground crops looks just a step up from raw sewage.
Yes, I have bought that one too.
Lef started with one greenhouse about an hour north of here.
Now, they have five throughout the eastern half of the country.
The biggest ones are 480,000 square feet. The lights are on 24/7 or when the sun is not out.
They use less water than lettuce grown outside.
‘gray water’................
>> Which means no illegals going #2 in the field.
THEY WOULDN’T DO THAT!!! ...would they?? 🤣
#############
With most of the ports potties usually located on one end of a field near a service road, it’s difficult to walk 1/4 mile or more when the workers gotta go to drop a deuce…so they don’t.
Most of these outbreaks are likely traceable to human urine or feces.
How do they compare in price to the national brands?
I only found them today after seeing your post; I’m going to check at my store.
All plant produce is picked by people with filthy hands... What else do you need to know?
If you cook it you ‘may’ remove the contaminates... Eating it raw is an unequivocal invitation to a weeklong toilet session. The good thing about meat... If you cook the hell out it, you’ll be just fine.
And yet the FDA and the USDA like to pretend that animal feces are the source of contamination.
I for one, welcome our robot field workers.
You know how it is,
you’re out in the middle of a giant field...
you have to take a dump...
the porta-potty is about a quarter mile away...
nobody’s lookin’...
I grow my own. Not the bland crap from the store. It is delicious and nutritious. There are many varieties never sold that can be home grown, selected for one’s region and taste, as well as nutritional content.
Yeah, pretty sure we can’t do anything about the poor irrigation systems they use.
I personally clean all produce in a bleach solution.
I honestly don’t know. I suspect they are a little more expensive. However, I know it is coming from a greenhouse within 50 miles of my house. Not shipped half way across the world in a container ship.
So, it is like paying $5/dozen of eggs because they come from the farm a mile from my house. Or the $15-20/pound I pay if I buy their rack of lamb. From the sheep that was born on their property and grazed in their field. Same story for the gelato they make from the sheep’s milk or the cheese.
The fact that this lettuce is grown in a greenhouse means that it is not covered in pesticides too.
Which is not that different than the blueberries that I grow on bushes in my yard. I cover them with nets to keep the birds off. I fertilizer them with organic fertilizer and do not spray them with an insecticide.
You’re so lucky. Neither of the two farms have lettuce in my area.
There seem to be a lot of greenhouse producers; it’s probably a growing idea;
https://nubiapage.com/top-10-largest-greenhouse-produce-growers-in-usa-2025/
My great aunt would wash all fruits and vegetables in vinegar water. It kills bacteria and removes pesticides.
They suggest vinegar to sanitize sprouting seeds, like alfalfa or mung seeds, too.
Clean Boss bump.
I buy this lettuce at several New England grocery chains.
Some of this companies greenhouses are as far south as Texas.
The good thing is that fresh lettuce at the one in Loudon, NH is still growing 24/7 in the middle of January. I am sure it costs more money to grow it in NH in the winter than it does other times of the year. Especially when it is minus 10 degrees outside.
I still would rather buy that then some grown in Chile that time of the year.
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