Utah expert explains why cyclospora persists in fresh produce each season
Food-safety specialist Dr. Jose Brandao says warm temperatures, contaminated water, sewage leaks and inadequate sanitation allow the cyclospora parasite to repeatedly enter produce, despite new safety regulations.
Utah health officials have recorded 48 cases of cyclosporiasis since May, none of which are linked to the current multi-state outbreak, but the parasite continues to appear in fresh produce each year. Dr. Jose Brandao, a food-safety specialist at Utah State University, said cyclospora thrives from May through August because warmer temperatures favor its incubation. He noted that human waste can reach agricultural water sources through sewage leaks, contaminated groundwater, or workers who lack access to proper toilet facilities. Heavy rain can carry fecal material from nearby sewage lines or fields into crop rows, and portable toilets that tip over or faulty sewage systems can further spread contamination.
"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.
"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," he added.
Irrigation, pesticide application and produce washing with contaminated water can introduce the parasite to consumers, and standard chlorine treatments do not eliminate it. Brandao explained that chlorine is intended to prevent cross-contamination from bacteria such as E. coli, salmonella and listeria, but it does not inactivate cyclospora.
"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.
He said the Food Modernization Safety Act and related training programs have improved farm practices, prompting growers to assess upstream contamination risks and adopt produce-safety rules. According to Brandao, most Utah farmers have embraced these measures.
"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.