Prevalence of parasitic contamination in vegetables used for raw consumption in Shahrekord, Iran: Influence of season and washing procedure

This study aimed to determine the prevalence of intestinal parasites in raw vegetables consumed in Shahrekord, Iran; and efficacy of season and washing procedures to remove parasites from the vegetables. A total of 304 field vegetable samples composed of parsley, spearmint, scallion, basil, coriander, dill, cress, leek, tarragon, radish and purslane were purchased from the vegetable markets. Each sample was divided into three groups. One group was used as the unwashed sample and the second and third groups were washed with traditional and standard washing procedures, respectively. Intestinal parasites were detected in 32.6% of unwashed, 1.3% of traditionally washed and not in any standard washed samples (P < 0.001). The parasites were detected in unwashed vegetable samples included Ascaris lumbricoides eggs (14.1%), Taeniid spp. eggs (9.2%), Toxocara spp. eggs (3.3%), Trichostrongylus spp. eggs (4.3%), Giardia spp. cysts (8.2%) and non-pathogenic protozoan Entamoeba coli cysts (9.2%). The rate of parasitic contamination in different seasons was found to be 55% in spring, 45.5% in summer, 14.9% in autumn and 12.3% in winter (P < 0.005). The results highlight the potential of unwashed raw vegetables in transmission of intestinal parasites to human, and also emphasize the use of standard washing procedure (proper washing and disinfecting) before consumption of vegetables instead of traditional procedure (quick washing without disinfecting).