Welcome to the US CDC’s Food Safety Education Month

Cyclospora cayetanesis, a microscopic parasite

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Jack Burnett
Technical Consulting Manager | Retail & Food Service
Sep 08, 2023

Cyclospora cayetanesis, a microscopic parasite, is a food safety concern that often flies under the radar. It can lead to Cyclosporiasis, causing uncomfortable symptoms such as diarrhoea, stomach cramps, and flu-like illnesses. The lifecycle of C. cayetanesis is a fascinating but concerning aspect of this parasite's biology. It begins when an infected person excretes C. cayetanesis oocysts (a thick-walled, dormant stage of the parasite) in their faeces. These oocysts can survive in the environment for months, potentially contaminating soil and water sources. When fresh produce is irrigated or washed with contaminated water or grown in contaminated soil, Cyclospora oocysts can adhere to the produce. Once ingested, the oocysts release sporozoites within the human digestive system. These sporozoites then invade the intestinal cells, renewing the cycle of infection.


C. cayetanesis is shed exclusively from the faeces of infected humans and can then contaminate water or soil used in agriculture. This poses a risk, especially to fresh produce that we consume raw. Here are some of the ways C. cayetanesis can end up in your fruits and vegetables:

  • Contaminated Water Sources: Irrigation water and wash water used during harvesting and processing can spread the parasite to crops.
  • Poor Hygiene Practices: Infected workers or improper hygiene practices during harvesting, handling, or packaging can transfer C. cayetanesis to the produce.
  • Contaminated Soil: Soil containing infected faeces can directly or indirectly contact produce during cultivation.


In recent years, there have been several noteworthy outbreaks attributed to C. cayetanesis. One notable outbreak occurred in the summer of 2018, where hundreds of people across multiple states in the United States fell ill due to C. cayetanesis infections linked to contaminated pre-packaged salad mixes and other fresh produce items. Similarly, in 2019, a significant outbreak associated with fresh basil affected consumers in several states. These outbreaks serve as reminders of the importance of stringent food safety measures, proper handling of produce, and continued research and surveillance efforts to detect and mitigate such incidents promptly.


Prevention and Produce Washing


The keyword here is “washing”. There are currently no EPA-registered biocides that are capable of inactivating C. cayetanesis oocytes while leaving the produce undamaged. The best way to control the risk of ingesting contaminated produce is by effectively washing the produce’s surfaces, with agitation and the assistance of a product designed for produce washing.

Here are some general best practices for risk-averse produce washing:


1. Choose the right product: For a food handling business, choosing a produce wash formulation is far from straightforward. Processes are regulated in different ways by various agencies- governmental and NGO. Regulatory requirements for post-wash rinsing vary depending on the chemical used and its concentration, the product’s organic status, and whether the desired outcome for the pathogen to remove, inactivate or prevent cross-contamination via the wash water.

2. Follow Instructions: Always read and follow the manufacturer's instructions on the produce wash product label. These instructions are designed to ensure optimal efficacy and safety.

3. Soak and Agitate: Submerge your produce in a solution of water and the produce wash chemical as per the recommended ratio. Gently agitate the produce to ensure thorough coverage. After soaking, rinse your produce thoroughly under cold, running water to remove any remaining soils and chemicals. 

4. Dry Properly: At home, use a clean towel or cloth to pat dry. If you’re a food processor, ensure your process is designed with efficient drying of the produce in mind. Then, store the produce in a clean and sanitary environment to prevent recontamination.


Following these guidelines and using produce wash chemicals correctly, you can reduce the risk of C. cayetanesis infection via fruits and vegetables, providing added peace of mind for your customers’ and families’ health.