Seasonal study of parasitic contamination in fresh salad vegetables marketed in Shahrekord, Iran

This survey was conducted to determine the parasitic contamination in fresh salad vegetables marketed in Shahrekord, Iran. The samples composed of unwashed and pre-washed cucumber, tomato, lettuce, cabbage, pepper, carrot, mushroom, and onion were purchased from vegetable markets. It was found that the rate of parasitic contamination was significantly higher (P < 0.05) in unwashed salad vegetables [25.2% (114/453)] than in pre-washed ones [6.03% (27/448)]. The parasites detected in unwashed salad vegetables included Ascaris lumbricoides (8.17%), Cryptosporidium spp. (2.87%), Enterobius vermicularis (2.65%), Taeniid spp. (4.86%), Strongyloides spp. (1.1%), Toxocara spp. (3.97%), and Entamoeba coli (2.43%). While the parasites namely A. lumbricoides (3.57%), Cryptosporidium spp. (1.79%), and E. vermicularis (1.12%) were detected in pre-washed ones. The rate of contamination in unwashed salad vegetables obtained during summer was significantly higher (P < 0.05) than those obtained during the other seasons. Occurrence of the parasites was the highest in lettuce, followed by cabbage and carrot both in unwashed and pre-washed vegetables. The unwashed field-origin vegetables like cucumber, tomato, and pepper showed significantly higher contamination (P < 0.05) than their greenhouse-origin counterparts. The results indicate the potential hazard of unwashed and pre-washed salad vegetables in transmission of parasites to humans, and also show the importance of proper washing before preparation of salads.