Abstract
Introduction: Vegetables contain many vital micronutrients, including vitamins and minerals, and are an important component of a healthy diet. However, they may be contaminated by pathogens present in contaminated soil, and water. Furthermore, the consumption of raw or insufficiently processed food pathogens, contaminated soil facilitates the transmission of enteric pathogens such as norovirus and Escherichia coli O157:H7 to humans.
Methods: This study aimed to assess the presence of human norovirus (HuNoV) genotypes I (GI) and II (GII), as well as E. coli O157:H7, in green leafy vegetables. Between December 2023 and June 2024, a total of 152 samples, including 38 lettuce, 38 watercress, 38 coriander, and 38 oregano, were collected from markets and farm gardens in the cities of Babol and Amol, located in Mazandaran Province. The reverse transcriptase polymerase chain reaction (RT-PCR) and conventional PCR were used to detect the targeted pathogens.
Results: The results revealed that 17 of 152 samples (11.18%; 95% CI: 6.65–17.30%) were positive for at least one of the target pathogens. Moreover, the contamination rates for HuNoV GI and GII were 1.97% (3/152) and 2.63% (4/152), respectively. E. coli O157:H7 was found in 6.58% (10/152) of the samples. Notably, the most positive samples were collected from farm-sourced vegetables. In addition, watercress exhibited the highest contamination rates for HuNoV GI (7.90%), HuNoV GII (2.63%), and E. coli O157:H7 (10.53%).
Conclusion: The results highlight the presence of several dangerous human enteric pathogens in leafy green vegetables. Considering the fecal-oral transmission route of these pathogens, their potential public health impact is substantial. Furthermore, the establishment of continuous, standardized surveillance systems is required to better understand environmental risk factors and to reduce contamination risks along the food supply chain.