The Food and Drug Administration has decided to detain fresh cilantro imported from Puebla, Mexico, until Aug. 31. That agency, the Centers for Disease Control and Prevention (CDC) and state public health officials and have identified three annually recurring outbreaks of cyclosporiasis associated with fresh cilantro from that state.

Mexican firms from the state of Puebla that have not already been approved must provide information to FDA that they have adopted measures that ensure the cilantro is picked, packed and prepares in sanitary conditions.

Another ongoing outbreak of cyclosporiasis began in May. The Texas Department of State Health Services, the Wisconsin Department of Health Services and the Wisconsin Department of Agriculture, Trade and Consumer Protection have identified cilantro from Puebla as the cause of separate illness clusters.

Cyclospora cayetanensis, a human-specific protozoan parasite, causes a prolonged and severe diarrheal illness known as cyclosporiasis. To become infectious, the organism requires a period outside of its host. Illnesses are known to be seasonal and the parasite is not known to be endemic to the United States.

People become infected with C. cayetanensis by ingesting sporulated oocysts, the infective form of the parasite. This most commonly occurs after a person consumes food or water contaminated with feces.  

The CDC and the FDA found cilantro from Puebla caused some of the U.S. cyclosporiasis infections in 2013 and 2014. After cyclosporiasis illnesses from the 2013 outbreak were linked to cilantro from Puebla, the FDA reviewed a cluster of 2012 illnesses in Texas and determined that cilantro from Puebla of was one potential source of that outbreak. However, this was not confirmed by epidemiological means.

The Texas Department of State Health Services has found cilantro from Puebla as the likely cause of this year's outbreak. Similarly, Wisconsin officials have identified a cluster of illnesses associated with a single restaurant's cilantro that also came from Puebla. The sources of these outbreaks are still under investigation.

The FDA believes it is extremely unlikely that these outbreaks of cyclosporiasis are due to isolated contamination events because of their recurring nature: They typically occur in April through August each year and they are repeatedly associated with cilantro from Puebla. No single supplier (including retail outlets or distribution centers), packing date, shipping date or lot code can explain all the illnesses. The source of C. cayetanensis contamination is likely attributable to a broader source of contamination, including fecal contamination of growing areas, irrigation of fields with contaminated water, cleaning or cooling produce with contaminated water, poor hygienic practices of workers who harvest and process the produce, and lack of adequate cleaning and sanitizing of equipment that comes in contact with the product.

The FDA and the Mexican regulatory authorities for farms, packing houses and processors in Mexico — Servicio Nacional de Sanidad, Inocuida y Calidad Agroalimentaria (SENASICA) and the Comision Federal para la Proteccion contra Riesgos Sanitarios (COFEPRIS) — investigated farms and packing houses in Mexico, including in the state of Puebla, to ascertain the conditions and practices that may have resulted in the contamination of cilantro. From 2013 to 2015, the FDA, SENASICA and COFEPRIS inspected 11 farms and packing houses that produce cilantro in the state of Puebla — five linked to the U.S. C. cayetanensis illnesses — and observed objectionable conditions at eight, including all five of the firms linked to the U.S. illnesses.

Based on those joint investigations, the FDA considers that the most likely routes of contamination of fresh cilantro are contact with the parasite shed from the intestinal tract of humans affecting the growing fields, harvesting, processing or packing activities, or contamination with the parasite through contaminated irrigation water, contaminated crop protectant sprays or contaminated wash waters.

The investigations lead the FDA to conclude that cilantro imported from the state of Puebla, Mexico, appears to have been prepared, packed, or held under insanitary conditions whereby it may have been rendered injurious to health. The seasonality of the previous C. cayetanensis outbreaks warrants detaining cilantro from the state of Puebla, Mexico, from April 1 through Aug. 31 of every year.