Is whole lettuce safer than pre-cut greens in a bag?

As the Spongebob cone of news silence dims any publicly available information about the romaine lettuce-linked E. coli O145 outbreak that has sickened more than 50 people, journalists find related stories to fill the void.

A common theme is – what can consumers do?

As I told CNN last week, the answer is, not much; fresh produce purchases are faith-based exercises in food safety.

Ask Douglas Powell, food safety expert and keeper of barfblog, whether he’d consider a salad of fresh romaine for dinner tonight.

If it’s lettuce from a grocery store, Powell’s answer is yes.

He bought some Wednesday, the day the Centers for Disease Control and Prevention expanded to four states a current outbreak of potentially deadly food-borne illness linked to tainted lettuce.

But would Powell put the green stuff on his plate at a salad bar? Absolutely not.

That’s because a current recall of romaine lettuce involves companies that distribute to wholesale and food service outlets. And because "salad bars in general have the potential for lots more contact with lots of hands and people."

Let me clarify. The romaine lettuce I bought was in a bag. And I ate from a salad bar the next night.

Lettuce is overrated, and I prefer my own variation of a Greek salad without the lettuce – red pepper, olives, garlic, herbs, feta cheese, cucumber, tomatoes and whatever else may be around, marinated in olive oil and red wine vinegar. I also eat the greens, grow some of my own (which will be ready for harvest in about three days) and buy the bagged stuff.

Mike Doyle, a microbiologist who directs the Center for Food Safety at the University of Georgia, told, if you want to reduce risks, "buy whole lettuce and cut it yourself."

Often, the bacteria lurk in the outer leaves. Nothing is foolproof, he said, but safety goes up when you toss the outer leaves and wash your hands properly.

Food safety lawyer Bill Marler said consumers should not give up eating a good thing out of fear. He also suggested that whole lettuce was a safer option than the bagged variety.

"Mass-produced lettuce is big business. The public wants it. But think hard whether the convenience is worth the risk."

I’m not sure I buy the higher-risk with bagged greens argument. I get that cross-contamination can happen when leaves are thrown in the same dump (wash) tank, but really, how hard is it to use a chlorine monitor and keep the water clean so the leaves aren’t washed in a muck?

The Washington Post reported this week it is difficult to judge whether pre-cut produce has been linked to more outbreaks than whole vegetables because state and federal health officials don’t always specify whether the leafy greens associated with an outbreak were bagged or whole. But several multi-state outbreaks involving pre-cut produce in the last five years have raised concerns, most notably the 2006 outbreak of E. coli O157:H7 associated with Dole bagged spinach that sickened 238 people and caused five deaths.

James Gorny, senior adviser for produce safety at the Food and Drug Administration, said bagged greens represent a disproportionate number of recalls, chiefly because they’re easier to identify than whole produce.

"When you buy a whole head of lettuce, you have no idea what the brand name is, or who the grower is. So tracing it back is that much harder."

But, he said, pre-cut produce is not inherently riskier than whole vegetables.

Dr. Doyle told the Post,

"I’ve been avoiding bagged lettuce for years. I’ve been concerned about this for some time."

Most processors of fresh-cut produce remove the outer leaves and core the heads of lettuce in the field, where cutting utensils can come into contact with soil and spread contamination from the dirt to the crop, Doyle said. In farming areas, especially in a region near cattle farms, it is not unusual to find E. coli in the soil.

In a study published last year in the Journal of Food Protection, Doyle and several colleagues contaminated coring devices with soil that contained E. coli O157:H7 — the most common E. coli strain associated with human illness — and showed how the bacteria spread from the coring equipment to heads of lettuce.

Washing the cored lettuce with a chlorine spray, a standard step, did not kill enough of the bacteria, the researchers found.

"In a processing plant, you’d have to have walls and clean floors. But here, they’re starting it right out in the dirt. It’s a very hazardous practice."

Once the bacteria attach to a lettuce leaf, "it’s very difficult to remove them," said Robert Gravani, a microbiologist at Cornell University. "We certainly want to increase our consumption of fresh fruits and vegetables, but we really have to address some of these issues."

To accurately compare the food safety risks of whole greens versus bagged greens, a database would have to somehow be constructed so that a comparison of illnesses on a per capita meal or even ingredient basis could be made. That is, people are eating a whole lot more of the bagged stuff these days.

What I told CNN was, production practices, harvesting, packing, processing and food handling have all been linked to illnesses associated with leafy greens. E. coli can get into food through manure, contaminated water used during growing or harvesting, or improper food handling at a store, restaurant or home. It’s best to ask a lot of questions of the people who sell you the green stuff. Was the irrigation water tested? Do the pickers know to properly wash their hands?

Beyond that, the only way to kill bacteria is to cook it. But who wants to eat mushy romaine?

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About Douglas Powell

A former professor of food safety and the publisher of, Powell is passionate about food, has five daughters, and is an OK goaltender in pickup hockey. Download Doug’s CV here. Dr. Douglas Powell editor, retired professor, food safety 3/289 Annerley Rd Annerley, Queensland 4103 61478222221 I am based in Brisbane, Australia, 15 hours ahead of Eastern Standard Time