The parasite fueling the ‘explosive’ diarrhea outbreak can't be washed off your produce — how to lower your risk and what to buy instead

In fact, the Centers for Disease Control and Prevention (CDC) announced Thursday that it’s either confirmed, or is investigating, more than 6,700 cases of cyclosporiasis caused by contaminated food which remains unidentified — though fresh produce has been the culprit in the past. Symptoms, they warned, include “watery diarrhea with frequent and sometimes explosive bowel movements” — among other unwelcome effects.

“A lot of times with diarrhea, you have an episode and you feel better,” Infectious Diseases Society of America CEO Jeanne Marrazzo told Wired. “With this, it just can kind of go on and on, and it really takes people out.”

The CDC adds that symptoms can appear up to a week after ingesting contaminated food and last between two days and two weeks. It also warned that the case count is likely much higher — and wider spread — than officials currently know of, because “some people recover without medical care and are not tested for cyclospora.”

What’s worse? The parasite is, evidently, a real clinger, attaching itself to fresh produce while remaining resistant to washing, sanitizer and even bleach — making it very difficult for consumers to ensure their produce is clean and safe to eat.

Salad greens are under scrutiny — but washing them won’t help

While the CDC hasn’t traced the source of the current cyclosporiasis outbreak, officials in Michigan, who are dealing with the nation’s largest single state outbreak, pointed the finger at lettuce or salad greens.

They caution, however, that “other food items cannot be completely ruled out” and that “no specific type of produce, grower, or supplier has been identified as the source.”

Michigan counts 3,762 cyclosporiasis cases as of July 15, while states from New York to Illinois, Kentucky and West Virginia also contend with outbreaks.

The FDA, meanwhile, added that “raspberries, basil, cilantro, snow peas and mesclun lettuce” have all been linked to previous cyclosporiasis outbreaks and warned that rinsing or washing food is not likely to remove the parasite.

In fact, they found that even “chlorine and other common anti-microbial chemical treatments are not effective” in removing it, though cooking does seem to kill it.

Meanwhile, as the outbreak surges ahead, some health officials target fast food chain Taco Bell for possibly contributing to the spread — and making customers run for the bathroom — via contaminated lettuce. No evidence, however, has been found to suggest this is the case.

Still, while cyclosporiasis outbreaks are reportedly rare in the U.S., the Associated Press reports that cases ticked up beginning in 2018, with 2019 proving the record year so far with around 4,700 cases reported — a number that 2026 may surpass.

The good news is that cyclosporiasis can be treated with antibiotics and rarely leads to hospitalization. No deaths have been reported in this current outbreak either.

However, the CDC identified May 1 to August 31 as “the annual cyclosporiasis season,” so the outbreak isn’t likely to die down anytime soon.

What to buy, cook and how to lower your cyclosporiasis risk

Since the CDC hasn’t identified an official food source for the cyclosporiasis outbreak, Americans should be extra cautious with the produce they buy and consume, as well as the cleanliness of the kitchens in which it’s prepared.

Given previous cyclosporiasis links to produce, Peter Chin-Hong, MD, a professor and infectious disease expert, told Bon Appétit that “lower risk choices include bananas, oranges, avocados, melon, mangoes” — while reiterating the importance of washing the skin and any knife used to cut into it.

He added that “commercial canning uses temperatures that can easily kill cyclospora,” so canned fruits and vegetables may also be an option.

The Michigan Department of Health and Human Services recommends consumers “buy whole heads of lettuce (rather than prewashed, bagged lettuce or salad mixes), throw away the outer two to three layers of leaves and wash the inner leaves under running water.” They add that cooking is the safest option for leafy greens.

They also say to “trim the root end and remove the outer layer” of green onions, washing the remainder thoroughly and cooking when possible. The cooking recommendation goes for snowpeas too, as well as fruits like raspberries, which they suggest making into jams.