Lab Matters Spring 2019 - Page 14

FOOD SAFETY Detecting Cyclospora in Food: FDA’s Success with a New Method during Outbreaks by Robyn Randolph, senior specialist, Food Laboratory Accreditation Protecting our food supply and preventing human illness is a core mission for the US Food and Drug Administration (FDA). In summer 2018, FDA led several investigations into multistate outbreaks of Cyclosporiasis, an intestinal illness caused by the parasite Cyclospora cayetanensis that sickened hundreds of people. Luckily, a newly-developed FDA food testing method allowed investigators to identify the pathogen in food or food articles, and remove implicated product from shelves quickly. Public Health Significance C. cayetanensis is not a newly emerging threat, as outbreaks have been associated with the parasite for years. However, both sporadic case reports and outbreaks of Cyclosporiasis are increasing based on surveillance data from the US Centers for Disease Control and Prevention (CDC). These increases could be due to improvements in surveillance methods, better diagnostic testing methods for human illness, or actual increases in illness due to yet-unknown factors. Whatever the reason for the reported increase in Cyclosporiasis cases, FDA’s development of a new Cyclospora food testing method was timely given last year’s large-scale outbreaks. Having a method to confirm the parasite’s presence in food commodities helps identify potentially contaminated products and hasten their removal from commerce. method for detection of C. cayetanensis in fresh produce such as leafy greens and berries. The Parasitology Program conducted a multi-laboratory validation to ensure the method’s accuracy and reproducibility. The method was published in 2017 in FDA’s Microbiological Methods & Bacteriological Analytical Manual (BAM) 1 , which lists the FDA’s preferred methods for pathogen detection. All seven FDA Office of Regulatory Affairs (ORA) Human and Animal Food (HAF) laboratories can conduct the Cyclospora analysis, with an ongoing expansion to state laboratories. Cyclospora Outbreaks in Summer 2018 Summer 2018 was a busy season with two large multi-state outbreaks attributed to C. cayetanensis. In June 2018, FDA 2 and CDC 3 worked together on a Cyclosporiasis multi-state outbreak in four states. As of September 2018, the CDC had been notified of 250 laboratory-confirmed cases of Cyclosporiasis from four states. Epidemiologic evidence pointed to pre-packaged vegetable trays. Unfortunately, traceback analysis was unable to determine the specific component of the vegetable tray that was responsible for the contamination. In July 2018, an even larger outbreak surfaced, with 511 laboratory-confirmed cases 4 from 15 states and New York City. Cases reported consuming salads from a major fast-food chain. FDA 5 was able to utilize the newly developed method to confirm the presence of C. cayetanensis in an unopened package of salad mix (romaine and carrots) distributed to the chain restaurants. Although a single source of contamination was not identified, FDA worked with the chain to stop selling salads in 14 states; the Validation of the New Method FDA has not been able to detect Cyclospora in food since the early 2000s, as the previous detection method relied on supplies that are no longer commercially available. Following large, multi-state Cyclosporiasis outbreaks in 2013, FDA’s Center for Food Safety and Applied Nutrition (CFSAN) created the Foodborne Parasitology Research Program to develop a new detection method. The Parasitology Program worked to adapt and improve a real-time polymerase chain reaction (PCR) 12 LAB MATTERS Spring 2019 FDA was able to utilize the newly developed method to confirm the presence of C. cayetanensis in an unopened package of salad mix (romaine and carrots) distributed to the chain restaurants. PublicHealthLabs @APHL APHL.org