Parasitic contamination of lettuce (Lactuca sativa) marketed in southern Brazil and its implications for food safety

The aim of is study was to evaluate the occurrence and parasitological profile of contamination in crisp lettuce marketed in Guarapuava, Paraná, Brazil. A total of 139 samples were collected from 45 supermarkets across 17 neighborhoods and analyzed using a spontaneous sedimentation technique, with identification based on morphological and morphometric criteria. Overall, 35.25% (49/139; 95% CI: 27.3–43.9) of the samples were positive for at least one parasitic structure, including coccidian oocysts (16.5%), larvated nematode eggs (12.2%), strongylid-type eggs (5.0%), and Toxocara spp. (1.4%). Morphometric analysis revealed significant variations in length and width among the detected parasitic structures (Kruskal-Wallis test, p < 0.001), supporting their differentiation. These results suggest that the contamination of lettuce by parasites remains a significant food safety concern and highlight the importance of adequate hygiene practices and surveillance along the production and retail chain.