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The Salmonella Outbreaks Among Peaches and Onions, Explained

Is foodborne illness everywhere this summer, or is it just us?

Red and yellow onions in a big pile. Photo: ra3rn/Shutterstock

For anyone whose interests lie in the intersection of fresh produce and food safety — or anyone who just doesn’t want to get sick from Salmonella — the month of August may have been nerve wracking, as two major Salmonella outbreaks prompted the recall of onions and peaches across multiple states, stores, and products. The onion-linked outbreak of Salmonella Newport has, as of August 18, resulted in 869 reported cases across 47 states, and more than 230 reported cases in Canada. Meanwhile, the peach-associated outbreak of Salmonella Enteritidis has led to 78 reported cases across 12 states, per the latest update on August 27.

While investigations by the Centers for Disease Control and Prevention (CDC), U.S. Food and Drug Administration (FDA), and other public health officials are still ongoing, the two outbreaks captured national media attention and concern. Eater spoke to five food safety experts, the CDC, and the FDA to find out more whether or not these back-to-back outbreaks are cause for alarm:

What is Salmonella and how can it infect people?

Salmonella is a genus of bacteria and one of the most frequently reported causes of foodborne illness. It’s transmitted through the fecal-oral route, meaning that humans consume food that has contaminated feces on it. Once it’s in the body, it can get into the gastrointestinal system and lead to infections, which can result in nausea, vomiting, diarrhea, cramps, and fever — symptoms that can be mild, but that can also lead to hospitalization or long-term health effects, according to Benjamin Chapman, a professor and food safety extension specialist at North Carolina State University.

Historically, Salmonella outbreaks have been associated with poultry, beef, and eggs, but the pathogen can be found in almost any source, including chocolate, petting zoos, pet animals, “you name it,” says Martin Wiedmann, a professor of food safety at Cornell University.

That includes fresh produce, such as onions and peaches. “Before the mid-’90s, we never really investigated foodborne illness outbreaks linked to fresh produce. Wasn’t because they weren’t happening, we just weren’t identifying them,” Chapman tells Eater. “The more we looked over the past couple of decades, the more prevalent fresh produce is as a source of foodborne illness.”

There are multiple ways that Salmonella can contaminate produce: humans (for example, harvesters), animals (both domesticated and wildlife), soil (including fertilizers and soil amendments), water (which can be contaminated from animals and then used for irrigation, or get to crops through flooding), and equipment and tools. Salmonella is “good at surviving under dry conditions as we might find on the surface of an onion or a peach,” says Donald Schaffner, a professor and extension specialist in food science at Rutgers University. The microorganism can also multiply in environments with favorable water, nutrient, and temperature conditions.

Why do the number of Salmonella-related recalls seem so prevalent recently? Are they actually prevalent, or does it just appear that way due to the attention these two cases have drawn?

Let’s get this out of the way: The two Salmonella outbreaks are not related, being genetically dissimilar, according to Peter Cassel, a press officer for the FDA. “We usually see more outbreaks of foodborne illness in the summer mainly because pathogens like Salmonella tend to do better in warmer weather/environments,” he says.

Michelle Danyluk, a professor of food science at the University of Florida, says it’s “all about perception.” Out of five multistate foodborne outbreaks so far this year, only two are linked to Salmonella; last year, there were seven. Overall, looking at the CDC’s National Outbreak Reporting System dashboard, the number of reported Salmonella outbreaks (defined as “when two or more people get the same illness from the same contaminated food or drink”) has remained relatively steady from 2009 to 2018.

The onion and peach recalls could be getting more attention because they are unusual sources. This is the first time a Salmonella outbreak has been associated with peaches, and onion recalls are not usually for whole bulb onions, according to Linda Harris, a specialist in cooperative extension and the department chair of food science and technology at the University of California, Davis.

The size and distribution of the outbreaks and recalls are also factors. While most reported outbreaks trace back to a single location — say, a restaurant in which one handler contaminated the food — multistate outbreaks suggest some source in, for instance, a farm or a packing facility before the product is shipped across the U.S. Furthermore, in addition to the produce itself, other foods were also recalled. “Onions are an ingredient in many foods and resulted in recalls of other foods containing onions, such as salsas and cheese dips,” says Matthew E. Wise, an epidemiologist and deputy branch chief for outbreak response and prevention at the CDC’s Division of Food, Water and Environmental Diseases. In the case of peaches, Wegmans bakery items containing peaches and Russ Davis Wholesale peach salsa were also recalled.

Finally, the timing of the outbreaks also likely contributed to the national story. Not only was the back-to-back emergence of these outbreaks noticeable, if not unheard of, but in the time of COVID-19, the public has a heightened awareness of infectious diseases, according to Chapman and Danyluk. “I think the way we are eating, and where we are eating, is a little bit different this year,” Danyluk says, “and we’re all a bit more sensitive to outbreaks.”

Are foodborne illnesses or outbreaks on the rise, more broadly?

There are an estimated 48 million cases of foodborne illness in the U.S. each year. While infections caused by certain pathogens may increase or decrease in any given year, overall, the number of estimated cases has remained steady, per Chapman. “That said, I think we could make the case that food is getting safer,” he says, “because at the same time that we’re not seeing an increase in outbreaks, our technology is getting better at actually finding them. What we see now, we might not have caught five years ago, and definitely not 10 to 15 years ago.”

Are foodborne illness outbreaks indicative of something unusual happening with our food supply or food safety systems?

It depends, as each outbreak is a little different, says Harris. “Sometimes the cause of an outbreak is identified, and sometimes that is a result of errors or mistakes made somewhere in the food system.” That may consist of a breakdown in a basic step like sanitation, or other protocols that people in our food supply should be following. There’s “no one place to point a finger,” per Harris.

The truth is, in most investigations, there may be a myriad of small things going wrong, and “we never find out exactly what the issue is,” Danyluk says.

One factor that drives the size of an outbreak is the speed of detection: If it takes 200 cases before public health authorities identify an outbreak, then the outbreak will be bigger. During the pandemic, it might take longer to detect an outbreak because people are simply less inclined to go to the doctor for a symptom like diarrhea, according to Wiedmann.

“It doesn’t mean a system is less safe, it’s just that things are different,” he says. “But there’s no evidence out there that the food supply is any less safe than it was eight or 12 months ago. It actually shows us that the system of detecting foodborne disease outbreaks is still working.”

Investigations of outbreaks may find gaps in the food safety system, but they are also vital for identifying areas for improvement in the future. Per Wise of the CDC: “Investigations can improve understanding of how contamination occurred at a specific point in the food supply chain, and lessons learned from investigations can help reduce or prevent future foodborne illnesses or outbreaks.”

TL;DR: Should the public be worried about these recalls?

Probably not. In the words of Wiedmann: “Life and food will never be zero risk. Driving in my car, anytime I go outside, I take a risk. Anytime I eat food, there is a risk.”

Foodborne disease cases will continue to happen because the food system is complex. But despite the risk — which Wiedmann emphasizes is “extremely small” — in general, experts say that consumers can continue to trust the safety of our food supply.

So what should consumers do with all these peaches and onions that may or may not be tainted by Salmonella?

It sucks to throw away a peach that may appear to be perfectly fine, but if public health agencies like the CDC and the FDA tell you to bin it, then bin it. (And don’t forget to clean and sanitize surfaces that have been touched by the foods in question.)

As Wiedmann says: “If there is a recall, you follow those recommendations.”

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