Why cyclospora keeps showing up in produce season after season

LOGAN — As federal and state officials continue monitoring a cyclospora outbreak, Utah health data shows none of the state's 48 reported cyclosporiasis cases since May have been linked to the current outbreak.

Still, cases of the illness appear every year, raising questions about why the parasite continues to contaminate fresh produce.

Cyclospora is a parasite that causes cyclosporiasis, an intestinal illness that comes from ingesting contaminated food and water.

According to Utah State University food safety specialist Dr. Jose Brandao, the parasite is particularly common from May through August.

"I don't have the full answer, but what I understand is that the pathogen prefers these warmer temperatures to incubate," he said.

Brandao explained the many ways human waste can enter agricultural water sources.

"We can have leakage from sewage into groundwater. We can have contamination from the workers. We can have a source of water that is contaminated, and no one is aware that it is contaminated," Brandao said.

Runoff can also create conditions that allow contamination to spread into crop fields.

"Let's say that we have a lot of rain and there is a portion of a field or sewage that is connected or close to a field, then we are going to get that into our production fields," Brandao said.

Workers can also unintentionally contribute to contamination.

"What happens if a worker is really far from the next portable toilet? He may not use a portable toilet and go into the field," Brandao said. "That automatically is not going to allow that feces to get to the food, but then we have rainwater or a storm that can contaminate the field."

Even when precautions are in place, accidents and infrastructure problems can create risks. Portable toilets can tip over, and sewage systems can leak without operators realizing there is a problem.

"Everything's working perfectly, but without anyone having the intention, it's percolating to groundwater, and it's contaminated the objects and fields," Brandao said.

Contaminated water can then be used for irrigation, pesticide application or washing produce, creating opportunities for the parasite to reach consumers.

Brandao said the parasite persists through the post-harvest process.

"Cyclospora is not removed by chlorine, and the reason of that chlorine is not to sanitize the produce; it's to avoid cross-contamination from foodborne pathogens," he said. "So it is protecting us from E.coli, salmonella, listeria, but sadly not cyclospora."

Brandao said updated food safety regulations through the Food Modernization Safety Act and training programs are helping reduce those risks. He said now, farmers have to think about possible contamination sources upstream, adjacent to or in their fields and do their best to eliminate them.

He said Utah farmers have generally embraced produce safety practices.

"As far as I know, I think that Utah is doing good work. Most of our farmers, they are trained in produce safety rules," he said.

Brandao said farmers who need help monitoring water quality can access food safety resources through Utah State University Extension and the Utah Department of Agriculture and Food. He said growers can also reach out to him directly for help at jose.brandao@usu.edu.

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