The FDA has outlined a ten-point plan to “mitigate” the risks of another cyclospora outbreak as it wrapped up an investigation linked to the lettuce recall.

Some 12,883 people were reported as being infected with cyclospora, the parasite that causes cyclosporiasis, by the US Food and Drug Administration stretching across 21 states from consuming iceberg lettuce linked to a farm in Mexico.

Two people were reported to have died amid 570 hospitalisations.

On Friday (2 October), the FDA said it had concluded its in-depth probe conducted in conjunction with the Centers for Disease Control and Prevention (CDC), which had declared the outbreak over on 11 September.

The cases were linked to an iceberg lettuce source in central Mexico, prompting the recall by Taylor Farms de Mexico, a supplier to sister company Taylor Fresh Foods in the US.

Explaining its findings of the tracing investigation and on-site inspections of “multiple” iceberg lettuce suppliers, the FDA said on Friday it had “identified several farms” and the facility in Mexico as providing the recalled veg.

Having sampled water, soil, sediment and actual iceberg lettuce, it found two positive results for cyclospora in Mexico.

“One positive sample was from a tank that held outgoing wastewater from the Taylor Farms de Mexico processing facility,” the FDA said. “The second positive sample was collected from a drainage ditch of an iceberg lettuce grower identified in the FDA’s traceback investigation.”

However, the regulator added: “While there is currently not enough evidence to conclusively determine how contamination occurred in this outbreak, the positive samples show that cyclospora was present in the environment where lettuce was grown and processed.

“This adds to the strong epidemiological data and traceback convergence supporting the link between this outbreak and recalled shredded iceberg lettuce from Taylor Farms de Mexico.”

Following the FDA’s conclusions, Mexico’s Ministry of Health, alongside the Federal Commission for Protection against Sanitary Risks (Cofepris), issued a response on the X social media platform on Saturday.

They noted the absence from the investigations in “determining which Mexican products caused the outbreaks”, while acknowledging the FDA’s findings.

Their post added: “It is important to clarify that the environmental findings do not, in themselves, constitute conclusive evidence that agricultural products were the source of contamination.

“Therefore, the information available at the close of both investigations does not allow for conclusive analytical evidence to establish that Mexican products were the source of the outbreaks.”

An analysis conducted by Cofepris’ National Reference Laboratory on raw materials, iceberg lettuce and water from the “investigated plant” also tested negative for cyclospora, they said.

Alongside its conclusions and the end of the cyclospora investigation, the FDA announced on Friday a “short-term” plan to “mitigate risks” for the 2027 growing season aimed at prevention in fresh produce.

The first among the plans are its outbreak investigation reports as detailed in last week’s wrapping up, in addition to increased surveillance of products “historically associated” with cyclospora.

It will also seek to engage the public at home and abroad to “raise awareness of current and prospective food-safety requirements”, complemented by improving testing capacity in Mexico.

The FDA will endeavour to extend data sources to evaluate “environmental factors” that could lead to the spread of cyclospora and then build prevention strategies.

Meanwhile in Mexico, the regulator said it will engage with Cofepris and agricultural agencies to improve food-safety education and reduce risks.

Another measure will be to look at how monitoring of water and waste management can be enhanced by hosting discussion panels to identify areas for improvement, while working alongside the CDC in “genotyping methods”.

Finally, the FDA will step up the use of Foreign Supplier Verification Program (FSVP) inspections to ensure importers are considering cyclospora in their “hazard analysis”, and bolster the Cyclospora Prevention, Response and Research Action Plan.