Eating Leafy Greens Safely

EATING Leafy Greens Safely from Consumer Report, March 2020

Many nutritionists declare that eating leafy greens are one of the hallmarks of eating a healthy diet.  This is true, but due to various environmental events this advice has been questioned.  The main culprit in this story is romaine lettuce that has too many times been implicated with outbreaks of food borne illnesses caused by a bacterium called E. coli.

Take the case of Cheryl in 1992.

Her mother, Susan knew something was wrong when she found her 6-year old daughter, Cheryl doubled up in pain and moaning. Her husband, Tom took her to the hospital after they realized Cheryl was also suffering from severe bloody diarrhea.  Susan and Tom spent the rest of the day wondering what was going on. Appendicitis was mentioned as a possibility.  By the morning, Cheryl was transferred to the ICU and given powerful painkillers. The next afternoon more tests  showed that Cheryl did not have appendicitis. Now what? New tubes were connected to Cheryl’s body, but her condition only worsened as the day wore on.

Cheryl continued to get worse which resulted in a heart attack and she was eventually put on life support; the damage to her heart and brain and kidneys were irreversible. The time had come to remove her ventilator. Susan sat there holding her six-year old daughter who five days previous had stayed home from school with a stomachache. Now she was gone.

The cause still remained a medical mystery until one physician had listed as a possible cause hemolytic-uremic syndrome (HUS), a rare disease leading to anemia and kidney failure. He had read that research identified E. coli as the primary cause of HUS. Most E. coli strains are harmless to humans, but one strain E. coli 0157:H7 can be deadly since  this bacterium manufactures a toxin that attacks red blood cells.  Stool cultures from Cheryl confirmed the presence of the E.coli O157:H7.

Soon other children had been infected and presented to emergency rooms over the Northwest U.S. “The headlines read: At least 45 people in Western Washington, most of them children, have fallen ill from an outbreak of a bacterial illness commonly linked to under-cooked beef, the state Department of Health officials said yesterday” The bacterium was identified as E. coli 0157:H7 and identified the source was hamburger meat served at a Jack in the Box restaurant that resulted in the death of four children and over seven hundred others who were gravely ill.  These potentially lethal outbreaks have forever changed America’s relationship with food. Previously, most consumers thought of food poisoning as a short-lived nuisance, if they thought of it at all. Now it has become more of a threat to the public and the produce industry in addition to the meat-industry.

Outbreaks Continue:  Consumer Reports, A Safety Guide to Leafy Greens, March 2020.

“According to the CDC, from 2006 and 2019 romaine and other leafy greens, such as bags of spinach and spring mix, have been involved in at least 46 multistate E. coli outbreaks. Some research shows that greens cause more cases of food poisoning than any other food, including beef.” According to the Centers for Disease Control and Prevention, 73,000 Americans become infected with this strain from all sources each year and about 60 people die as a result.

“Many victims of these outbreaks have had their lives seriously disrupted. Many have needed kidney transplants and hundreds of thousands of dollars in medical expenses because they chose to eat a presumably healthy food,” says Bill Marler, a food safety lawyer in Seattle who negotiated settlements for many victims.

For every reported case, there are many, many more cases that are not reported, says the CDC. Something has gone wrong with the processing practices we now employ and can occur during any of the steps required to grow, harvest, and package salad greens. Salad greens in the U.S. are primarily grown in two main areas: Salinas Valley, California and Yuma, Arizona, depending on the season.

However, leafy greens, especially romaine lettuce have consistently been found to be the culprit in a great majority of cases from all causes. Sales of romaine have plummeted from sales of $563 million in 2017 to $465 million presently. Still, growers are trying to figure out at what stage of the plant’s growth, a potentially deadly bacteria finds its way into and onto lettuce leaves. As bacteria are killed in products that are consumed after cooking, salads are usually eaten raw. In raw foods, this final “kill” step of cooking simply does not exist making it more difficult to contain any outbreaks. Even more simply, consumer demand for salad greens has increased significantly. Romaine became the trendy lettuce and popular for salads, burritos, wraps. Even most mixed greens bags contain some romaine.

How Greens Become Contaminated

Growing the Seeds

Bacteria such as E. coli are found in animal feces from cattle and sheep and the leaves of the growing plants can take up the microbes into their roots and thus the leaves.  Many of these lettuce farms are unfortunately found close to animal feedlots and the runoff from the feedlot waste ends up into the water used to irrigate the growing crops. It also may be carried by the wind from feedlots onto the adjacent growing plants. Wild animals or birds can deposit bacteria onto the fields. One major outbreak was attributed to the presence of wild boar contaminating the fields.

Harvesting the Fields

Machinery that helps to harvest may carry bacteria onto the fields.  Workers may not practice proper hand washing when harvesting crops (this is hard to maintain in the field setting. When plant leaves are cut during harvesting, the ends provide a reservoir of nutrients for the bacteria to thrive on and bacteria to enter the leaves.

Processing Plants

For bagged greens, plants from many sources are mixed together. If there is even one contaminated leaf in the mix, the rest will soon become contaminated as well. Equipment is not sanitized properly, and workers do not practice adequate hand washing procedures. Greens are washed in a sanitizing solution that may be recycled.

Triple-washed Greens

Most consumers feel reassured when buying bagged greens that state on the label, “Triple-washed, Ready to Eat. This creates a false sense of security since most bacteria are almost impossible to remove. It only takes 10 microscopic bacterial cells of E. coli, for example, to be considered an infectious dose. Therefore, this process may cut bacterial contamination, but it does not guarantee all the bacteria are “killed.”

Fifty-six percent of Americans rinse their lettuce before eating it, but mere water does little to remove harmful bacteria. Bagged lettuce contains greens from many farms and the leaves have all been cut. ” According to the results from a 2006 spinach outbreak, the tainted greens were eventually traced to one small section of just one small section of just one growers’ field.”

Prevention

Prevention is a complicated problem. More regulations are needed, but growers say they have already made most of the changes that are known to improve food safety.  “There’s no such thing as zero risk” according to Channah Rock, Ph.D., a researcher.  People need to be alerted to outbreaks and recalls more quickly to stop the contaminated food from reaching the market. In my opinion, feedlots should not be allowed to operate so close to produce fields – and stricter water testing is needed. As with all regulations, delays are inevitable. For example, stricter rules were implemented to take place in 2018. Now they have been pushed out to at least 2022.  Delays like this are unacceptable when consumers’ lives are involved.

The Safest Ways to Eat Salad

Even though there are problems, in my opinion, consumers should know the facts of the hazards and make their own decisions as to whether to eat raw salad greens or not. 25% of Americans say they eat lettuce less often now than before. I personally avoid raw salads but find this unfortunate due to their high nutrient density and recommendations to eat more fruits and vegetables. Here Is what you can do until the industry can make greens less risky.

  • Cook sturdier greens until wilted: Use spinach, kale, collards, Swiss chard, bok choy
  • Consider buying whole head lettuce, not bagged. The heads are less processed, cut, and easier to wash before eating. Their inner leaves are more protected and are less likely to meet with sources of contamination.
  • Keep packaged lettuce cold and eat it soon. Bacteria grow more quickly at room temperatures. Watch the expiration dates. Do not use damaged or bruised leaves.
  • Look for hydroponic or green-house grown greens. These are more protected against animal droppings in soil or water. Cleanliness depends on the water source and hand hygiene of the workers.
  • Soak greens in white vinegar for 10 minutes, then rinse. This will only reduce bacteria levels, not kill all bacteria. Forget salad rinses that only will clean off dirt or chemicals. They do not kill bacteria.
  • Stay informed. You can follow recalls at FDAfood and USDAFoodSafety. On either sites, you can sign up for email alerts.

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