Molecular investigation of ready-to-eat salads for Giardia duodenalisand Cryptosporidiumspp. in Portugal

Foodborne outbreaks are often associated with the consumption of salads. However, published studies on the detection of foodborne pathogens in ready-to-eat salads are scarce. The aim of this study was to detect Giardia duodenalisand CryptosporidiumDNA in ready-to-eat salads, by applying techniques of molecular biology to study the frequency of contamination in salads. A total of 100 packages of ready-to-eat salads containing assorted leafy green vegetables were randomly purchased from hypermarkets located in central regions of Portugal (Coimbra and Viseu). Nested-PCR and qPCR methods were used to detect G. duodenalisand CryptosporidiumDNA. Species and assemblages of the parasites were identified by sequence analysis and PCR. Eighteen of the 100 samples (18%) were positive for G. duodenalisand twelve were sequenced and identified as assemblage A. Cryptosporidiumspp. were not detected in any salads. Overall, pre-harvest and post-harvest preventive measures may be need for G. duodenaliscontrol throughout the food production industry, from the field to consumers.