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P1-18 Comparison of Detection of Cyclospora cayetanensis in a Variety of Food Matrices

Monday, July 10, 2017
Exhibit Hall (Tampa Convention Center)
Sonia Almeria , U.S. Food and Drug Administration–CFSAN, Office of Applied Research and Safety Assessment , Laurel , MD
Alexandre da Silva , U.S. Food and Drug Administration–CFSAN, Office of Applied Research and Safety Assessment , Laurel , MD
Mauricio Durigan , U.S. Food and Drug Administration–CFSAN, Office of Applied Research and Safety Assessment , Laurel , MD
Tyann Blessingnton , U.S. Food and Drug Administration , Laurel , MD
Helen Murphy , U.S. Food and Drug Administration–CFSAN, Office of Applied Research and Safety Assessment , Laurel , MD
Introduction:  Cyclospora cayetanensis is a major cause of diarrheal illness and outbreaks; however, microbiological sampling and surveillance is limited due to the lack of validated methods for produce. In 2016 a method for detection of C. cayetanensis in cilantro and raspberries was validated by the U.S. FDA for regulatory testing. In 2016, a restaurant-associated subcluster of cyclosporiasis illnesses were epidemiologically linked to consumption of cole slaw containing shredded carrots and cabbage. Therefore, it is imperative to evaluate the performance of this validated method in different matrices.

Purpose: This study evaluated the validated method to detect C. cayetanensis in commodities, other than cilantro and raspberries, and compared the results.

Methods: A total of 25 grams shredded carrots and cilantro and 50 grams raspberries were seeded with 5, 10, 20, and/or 200 C. cayetanensis oocysts from Nepal. Unseeded produce were used as negative controls. The method included washing of the produce, extraction of C. cayetanensis DNA, and molecular detection using a TaqMan assay targeting the 18S rRNA gene.

Results: Detection rates in shredded carrots were 26.7% of 15 samples seeded with 10 oocysts and 56.2% of 16 samples seeded with 20 oocysts. All carrot samples seeded with 200 oocysts (n=11) were positive and all unseeded carrot samples (n=11) were negative. Comparatively, C. cayetanensis oocysts detection rates for cilantro and raspberries seeded with 5 and 10 oocysts were 31.3% and 80.0%, and 50.0% and 90.0%, respectively, in a multilaboratory validation study.

Significance: The method was slightly less sensitive for detection of C. cayetanensis in shredded carrot samples when compared to the results observed in cilantro and raspberries. This study highlights the importance of evaluating the performance of the C. cayetanensis detection method in different food matrices as the U.S. FDA advances with the implementation of such tools for regulatory purposes.

Back to: Poster Session 1 – Viruses and Parasites, Beverages and Acid/Acidified Foods, Preharvest Food Safety, General Microbiology, Food Defense, Food Law and Regulation, Food Safety Systems, Food Processing Technologies, Modeling and Risk Assessment, Sanitation and Hygiene, and Antimicrobials
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