Parasitological Contamination of Vegetables Sold in Tunisian Retail Markets with Helminth Eggs and Protozoan Cysts

Abstract

<jats:sec> <jats:title>ABSTRACT</jats:title> <jats:p>Foodborne diseases continue to represent an important threat to public health in many parts of the world and are particularly widespread in developing countries. They are essentially acquired through an oro-fecal route via the consumption of uncooked fruits and vegetables. This study evaluated the parasitological contamination of vegetables for sale to humans in Tunisian retail markets. A total of 240 samples of fresh vegetables were examined for helminth eggs and protozoan cysts and oocysts (collectively, (oo)cysts) contamination. The parasitic elements (helminth eggs and protozoan (oo)cysts) were concentrated by sucrose flotation and identified by microscopic examination. The molecular identification of Echinococcus granulosus eggs was carried out using PCR. Helminth eggs and protozoan (oo)cysts eggs were found in 12.5% of the unwashed vegetables, and the most common parasites observed in vegetables were coccidian oocysts (4.1%), Toxocara spp. (2.5%), hookworm (2.1%), and Taenia spp. (1.25%) eggs, followed by Pseudolimax butschlii (1.6%) and Entamoeba coli (1.6%) protozoan cysts. Furthermore, parasite contamination differed significantly from one city to another. Taeniid eggs were identified by PCR as E. granulosus sensu stricto (s.s.) (genotype G1). To our knowledge, this study highlights for the first time in Tunisia that fresh vegetables for sale in markets are contaminated with helminths and protozoan cysts, which are potentially pathogenic for humans. The control of these pathogens is in part a question of sanitary education, especially for retail vendors, and in part of improvement in hygiene measures throughout the food production chain, from the field to the consumer.</jats:p> </jats:sec> <jats:sec> <jats:title>HIGHLIGHTS</jats:title> </jats:sec>

Detection of human intestinal protozoan parasites in vegetables and fruits: a review

“…The PCR technique is also commonly used to detect Entamoeba spp. in food items based on amplification and sequencing of specific genes [ 23 , 53 ].…”

Contamination of Soil, Water, Fresh Produce, and Bivalve Mollusks with Toxoplasma gondii Oocysts: A Systematic Review

“…e Detection rate not given, calculated based on the data reported. Articles with results only or also based on microscopy assay or other methods that were not specified: [ 120 , 122 , 123 , 124 , 125 , 126 , 127 , 128 , 129 ].…”

Diagnostic tools for the detection of taeniid eggs in different environmental matrices: A systematic review.

“…(non-molecular part) E. granulosus (PCR) Fresh vegetables (chard, celery, lettuce, etc.) Quantitative (non-molecular part) and semi-quantitative (PCR) N.M. N.M. 10 ≤ 36 h Tunisia M'Rad et al, 2020 Washing (Tween 20), filtration, Calcium Fluor white staining, microscopy and SYBR green real-time qPCR ( nad1 gene) E. multilocularis Bilberreis and lingonberries Semi-quantitative LOD: 50 eggs/250 g berries At −20 °C until analysis 11 ≤ 24 h Finland and Estonia Malkamäki et al, 2019a Washing (Tween 80), sedimentation, centrifugation, ZnCl 2 (s.g. 1.4) flotation and nested end-point PCR (12S rRNA gene) E. multilocularis Berries, mushrooms, and vegetables (lettuce, beets, celery, etc.) Semi-quantitative LOD: 100 eggs/ 400 g In disposable bags 12 ≤ 48 h Poland Lass et al, 2015 Berries, mushrooms, and vegetables (lettuce, beets, celery, etc.)…”

“…( Table 2 ). An end-point PCR targeting the 12S rRNA gene from E. granulosus was described by M'Rad et al (2020) . No specific DNA extraction kit was mentioned, but the DNA was extracted by alkaline lysis and proteinase K digestion, and chelating resins to trap DNA contaminants.…”