From Farm to Fork: Parasitic Contamination of Raw Vegetables and Implications for Food Safety and Sustainable Development

Abstract

Background: Raw vegetables are widely regarded as a basic component in healthy foods and are used as vectors in cases where intestinal parasites are not eliminated from them properly. The current study aimed to evaluate the prevalence and distribution among various taxonomic groups affected by parasites in commonly eaten leafy and non-leafy vegetables from markets and grocery stores in relation to food safety and sustainable development objectives. Methods: A cross-sectional survey of 126 samples of vegetables (63 leafy, 63 non-leafy) from May through September of the year 2025 was undertaken. Adherent material (200–300g) of each sample was rinsed with 500mL of sterile saline, allowed to settle, then centrifuged, and analyzed under light microscopy with the use of wet mounts and the flotation concentration methods; iodine staining, when applicable. The data were analyzed for differences in contamination rates of the vegetables using the Chi Square test of Pearson. Results: Overall, 67/126, 53.2% samples were positive for at least one intestinal parasite. Contamination was significantly higher in leafy vegetables than in non-leafy vegetables (55/63, 87.3% vs 12/63, 19.0%; χ2 = 59.0, p < 0.0001). Samples from open markets showed higher prevalence compared to those from grocery stores (50/84, 60.0% vs 17/42, 40.5%; χ2 = 4.67, p = 0.031). Single-taxon detections (n = 67) included Giardia lamblia cysts (25/126; 19.8%), Ascaris species ova (20/126; 15.9%), non speciated nematode larvae (12/126; 9.5%), Entamoeba histolytica/dispar cysts (7/126; 5.6%), Taenia species ova (2/126; 1.6%) and Hymenolepis nana ova (1/126; 0.8%). All the above detections were associated with leafy produce and open market sourcing. Conclusions: Leafy vegetables and produce handled under the conditions of informal market environments were determined to serve as main reservoirs of intestinal parasites. The results point to the necessity of implementing interventions aimed at enhancing the quality of irrigation waters, manure treatment, hygiene, as well as hygiene practices among vendors in the market, for the control of foodborne parasitic diseases.

Keywords: fresh vegetables; soil-transmitted parasites; food safety; leafy vegetables; prevalence.