Why food safety experts are avoiding E. coli

An outbreak of E. coli that has sickened at least 75, killing oneis a reminder of the risk of contamination that can affect certain types of fresh produce, according to food safety experts.

The four teachers said they themselves routinely avoid certain raw fruits and vegetables, such as kale, bagged lettuce and cantaloupe.

Although the investigation is ongoing, federal officials suspect prewashed, chopped onions that were served raw on McDonald’s Quarter Pounders are the likely source of the E. coli outbreak. For those who specialize in foodborne illness prevention, the news came as no surprise.

Don Schaffner, a professor of food science at Rutgers University, said the more food is handled and processed on its journey from the farm to a restaurant or grocery store, the more opportunities there are to introduce or spread bacteria. This includes slicing, pre-washing or adding ingredients.

“The more manipulation you do, the more places there are for things to go wrong,” Schaffner said.

By its very nature, when fruits and vegetables are served uncooked, there is no opportunity to heat the bacteria. This has contributed to previous product-related E. coli outbreaks, including a Outbreak since 2006 in prepackaged baby spinach which sickened over 200 and dozens of cases of E. coli and other foodborne illnesses that have been associated with contaminated sprouts. Cantaloupe has also been contaminated with pathogens including salmonella and Lister.

“If we just look at the large number of outbreaks and recalls over the last 15 years, we typically see more E. coli cases related to production,” said Darin Detwiler, professor of food regulatory policy at Northeastern University.

Although there have been serious incidents of E. coli decades ago in meat — including an outbreak linked to Jack in the Box hamburgers that made hundreds of sick people and killed four in the early 1990s – changes in federal regulations and a better understanding of the proper cooking temperatures needed to kill bacteria have reduced these cases.

Barbara Kowalcyk, director of the Institute for Food Safety and Nutrition Security at George Washington University’s Milken School of Public Health, said she makes an effort to avoid eating bagged greens, kale and cantaloupe. Bags or containers that hold lettuce or other leafy greens can seal in bacteria and create an environment for it to proliferate, she said, so for salads, she opts for heads of lettuce at the grocery store.

“Any leaf that’s torn or damaged, I throw it away because that’s how bacteria can get in there,” she said. “And I usually take the outer leaves off and throw them away.”

Then wash well and dry the lettuce.

“The key is running water and using a clean paper towel to dry it,” she said. “Bacteria are kind of sticky, and the friction is what removes them.”

Schaffner said previous E. coli outbreaks involving prewashed green leafy vegetables resulted from a lack of chlorine in the water while they were being rinsed. With sprouts, it’s another concern, he said: The seeds are exposed to warm temperatures, and as they sprout, they release nutrients into the water that allow bacteria to grow.

Cut melons, meanwhile, can be a common breeding ground for pathogens, especially if left outside.

“I do a lot of workshops, and often they have cut fruit in the breakfast buffet, and that fruit stays there all day,” Schaffner said. “We’ve done research to show that its physical appearance doesn’t change, but it can grow bacteria like nobody’s business.”

Detwiler is particularly careful to avoid cantaloupe because of its rind, where bacteria can easily hide.

“It’s one of the deadliest products out there, of all,” he said. “Cantaloupe has a perfect pH and you can’t clean the outside enough.”

E. coli spreads in the environment through animal or human faeces and from there it can contaminate food and water. While significant improvements in agriculture have minimized the spread of pathogens in the fields where produce is grown, experts said it’s still important for consumers to consider the risk of E. coli — especially for young children, people over 65 and anyone with a compromised immune system, including those who are pregnant.

“This is a really unique pathogen because there is a very low infectious dose. So it may only take a few cells to make someone sick,” said Kali Kniel, a professor of microbial food safety at the University of Delaware.

The food safety experts interviewed also said they avoid rare or undercooked meat, poultry, fish, and eggs, and they don’t drink unpasteurized milk.

Some also mentioned looking for signs of cleanliness when dining out.

“If I walk into a restaurant I’m not familiar with, one of the first things I do is go to the bathroom, because if the bathroom looks horrible — like nobody’s cleaned it in a long time — I don’t. I really want to know what the kitchen looks like,” Detwiler said.

That said, fast-food restaurants are generally not a hotbed for foodborne illness, and Detwiler said McDonald’s has a “long history of being a very prominent leader” in food safety.

Kowalcyk agreed, adding that as a large chain, McDonald’s probably has more procedures in place to train employees about contamination prevention.

“I don’t think any particular type of restaurant is more risky than others, except that large organizations tend to have a lot of resources and smaller organizations tend to have less resources or expertise,” she said.

Raw onions were not previously known to be related to an outbreak of this particular strain of E. coli, according to the Centers for Disease Control and Prevention. But onions have been contaminated with pathogens in recent years: Salmonella outbreak were related to them.

Kniel said he expects improvements to be made as a result of the increasing number of E. coli cases.

“We learn something every time there’s an outbreak,” she said.

For consumers concerned about E. coli, Schaffner acknowledged that it is impossible to avoid every product that has been linked to foodborne illness.

“Stopping food when it’s linked to outbreaks would leave you with too much of a diet,” he said. “As a good friend of mine used to joke, the risks of not eating still outweigh the risks of eating.”