Parasites in Fresh Produce: a Brazilian Inter-laboratory Evaluation of a Standardized Methodology for the Detection of Ascaris sp. in Leafy Vegetables

Abstract

Vegetables are potential vehicles for the transmission of parasites. Helminth eggs have been detected in produce in various countries around the world, with high prevalence rates. However, there is no standard validated method or ISO to the isolation, concentration, and identification of helminth eggs in salad vegetables, which makes comparison difficult since each study utilized different analytical methods and food matrix. The purpose of the present study was to evaluate the effectiveness of a previously described methodology developed for the recovery of Ascaris sp. eggs in two different leaf greens under real conditions of use, through the simultaneous application of the same method by ten different laboratories. This is the first collaborative inter-laboratory trial by several laboratories across Brazil. Lettuce and arugula samples artificially contaminated with A. suum eggs were analyzed by various laboratories to determine the recovery efficiency of Ascaris sp. eggs. A final mean recovery efficiency of 57.10% for Ascaris sp. eggs in lettuce and 50.7% in arugula was identified. The methodology applied in this study can be used to evaluate Ascaris sp. eggs in vegetables. It is reasonably easy, fast, and efficient in comparison with other methods. The identification of helminth eggs in fresh vegetables using a reliable methodology is important if the microbiological safety of these foods is to be improved.