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
Helen Murphy
, U.S. Food and Drug Administration–CFSAN, Office of Applied Research and Safety Assessment
, Laurel
, MD
Amy Kahler
, Centers for Disease Control and Prevention, Division of Foodborne, Waterborne and Environmental Diseases
, Atlanta
, GA
Mia Mattioli
, Centers for Disease Control and Prevention, Division of Foodborne, Waterborne and Environmental Diseases
, Atlanta
, GA
Jannifer Murphy
, Centers for Disease Control and Prevention, Division of Foodborne, Waterborne and Environmental Diseases
, Atlanta
, GA
Vincent Hill
, Centers for Disease Control and Prevention, Division of Foodborne, Waterborne and Environmental Diseases
, Atlanta
, GA
Introduction: Filtration methods, such as USEPA Method 1623, used for the recovery of parasite oocysts and cysts, play an essential role in confirming or ruling out irrigation water as a potential vehicle for contamination of produce. However, there is limited information regarding the comparative performance of Method 1623, relative to other large volume sampling methods for recovery of the parasite,
Cyclospora cayetanensis, from agricultural water samples.
Purpose: This study compared the CDC’s dead-end ultrafiltration method (DEUF) with the use of Envirocheck microfilters per Method 1623 for recovery of C. cayetanensis from irrigation pond water with various turbidities. Both methods have been widely used for recovery of Cryptosporidium oocysts and Giardia cysts, but have not yet been validated for C. cayetanensis.
Methods: Two sets of 50-L agricultural water samples that represented low and high turbidity (0.71 and 21.6 NTU average, respectively) were each seeded with approximately 162 oocysts/liter and processed using both filtration methods. A qPCR assay, validated by the U.S. FDA for the detection of C. cayetanensis in produce, was used to quantify C. cayetanensis in the concentrates. The experiments were repeated five times for each filtration method.
Results: For both DEUF and Method 1623, C. cayetanensis was detected in five of five high and low turbidity water samples.
Significance: This comparative study demonstrated that the DEUF method performance was not significantly different than Method 1623 Envirocheck filtration in the recovery of C. cayetanensis oocysts from agricultural water with various turbidity levels. However, the DEUF is less expensive and less prone to clogging, allowing for processing of larger and lower quality water samples.
