Cyclospora Outbreaks and How to Mitigate Risk
What is Cyclospora?
Endemic to tropical and subtropical regions, Cyclospora is a parasite commonly found in contaminated food and water. Most of the cases reported in the UK are people who have traveled in the Caribbean, Mexico, Central and South America, South and East Asia, the Middle East, and Africa. The species Cyclospora cayetanensis causes an emerging infectious disease in both developing and developed countries called cyclosporiasis. If infected, people may suffer from explosive watery diarrhea, loss of appetite, weight loss, stomach cramps, nausea, excessive gas, and other gut manifestations.
What is the impact of Cyclospora on commercial produce?
Cyclospora cayetanensis is not transmissible from person to person. Because of its life cycle, the parasite needs some time to transform to an infective stage after being passed in a bowel movement. As such, the carriers of the disease are often drinking water and eating fresh produce contaminated with Cyclospora-infected feces, whether through the irrigation water or the soil.
In the U.S., the past cyclosporiasis outbreaks were linked with the consumption of raspberries, basil, cilantro, snow peas, and Mesclun lettuce imported from developing regions. The Centers for Disease Control and Prevention (CDC) reported 1065 cases from 40 states and 52 hospitalizations. Further, researchers observed and isolated Cyclospora-oocysts from the fresh produce sold in Italy. Based on microscopic and molecular data, the "ready-to-eat" mixed salads and blueberries sold in Italian fresh markets were also infected with Cyclospora. However, not all cases resulted from the consumption of imported products. The FDA also confirmed the presence of the parasite in domestically grown cilantro in July 2020. Recent findings within domestic produce indicate that this pathogen is no longer a risk originating from imported product or travelers.
What research is being done to test for Cyclospora in produce?
Testing for this parasite is particularly challenging since scientists have not identified a way to propagate Cyclospora cayetanensis in vivo or in vitro. As such, testing methods rely on concentrating oocysts on produce or in water; this concentration leads to longer testing times, demands for very high ability to detect at low levels and is complicated by the short life of the fresh produce. Due to these constraints, it is very challenging to find Cyclospora on product. If the produce item or dish has several ingredients as in the mixed salads or herbs used as garnish, food safety procedures require more complex epidemiological investigations that can slow trace back.
Despite these roadblocks, there are tools to detect C. cayetanensis in food. Barlaam and colleagues used microscopy with FLOTAC double technique to analyze produce samples and detect the parasite in the commercial produce from an Italian market. The researchers verified the results using different molecular techniques such as DNA extraction and simple quantitative polymerase chain reaction (qPCR), conventional nested PCR, and multiplex qPCR to simultaneously detect other parasites aside from Cyclospora. In another study, Shapiro and colleagues used nested PCR of 18S rRNA gene of Cyclospora, combined with restriction fragment polymorphism (RFLP), a more targeted technique that differentiates Cyclospora from the closely related Eimeria.
In 2017, the U.S. Food and Drug Administration (FDA) developed a regulatory method to detect C. cayetanensis in produce. This method uses an enhanced washing solution to recover the oocysts and to disrupt them to release the DNA. The DNA is then purified and examined using real-time PCR for identification. The developed method was already highly consistent and reproducible for the detection of the parasite, but Almeria and colleagues optimized it further by using 1% Alconox® instead of only 0.1%, as was previously proposed. This change in the methods made the oocyst extraction from produce more efficient.
Are there any known processing steps to mitigate Cyclospora risk?
Simple washing and rinsing of the food aren't likely to remove the parasites. As such, the brunt of work falls mainly on the producers, farmers, and suppliers. Detecting and identifying Cyclospora can minimize microbial hazards in food, but other technologies are also available to prevent the contamination of the produce in the first place. For instance, some researchers use dead-end ultrafiltration (DEUF) of the irrigation water to detect the parasite in environmental and agricultural waters before they are used to grow the produce.
Reduce Risk of Microbial Contamination in Your Food Products
As a supplier, you also have a responsibility to control the sources of contamination in the field and packinghouses to reduce Cyclospora risk and minimize microbial contamination in your produce. If you control the growing and harvesting of fresh fruits and vegetables, train your farm workers on how to properly use the toilet facilities, including the sanitary disposal of toilet paper, and provide regular training about food safety. You can also hire a contractor to clean and sanitize the portable toilets, and make sure that they dispose of human waste into an appropriate sewage system. Further, you can employ a municipal wastewater treatment that will kill C. cayetanensis.
Lastly, partner with a trusted laboratory with specialized food testing and food safety services. Eurofins Scientific, Inc. ensures the quality, safety, and integrity of food products with recognized analytical and microbiological testing services focused on food safety management. Contact us for optimized, cost-effective effective food safety services custom-tailored to your company's needs.
