Influence of conventional, agroecological, and hydroponic farming methods on the microbiological quality, isotopic and mineral composition of arugula (Eruca sativa).

Abstract

The safety and nutritional quality of leafy vegetables are influenced by various cultivation practices; however, data comparing agroecological, conventional, and hydroponic systems remain limited. This study aimed to evaluate differences in Eruca sativa (arugula) grown under these systems, focusing on microbiological quality, levels of inorganic elements, and potential health implications of consumption. Additionally, it explores whether combining these parameters with δ¹⁵N analysis can effectively distinguish between arugula from different farming systems. Microbiological analysis revealed superior quality of hydroponic arugula, as fecal coliforms, Escherichia coli, and Salmonella spp. were not detected in any sample. Diverse essential and toxic elements were found in arugula, with Cd, Fe, Mn, Ni, Pb, and Sr present in higher concentrations in conventional and agroecological samples. Conversely, hydroponic arugula presented higher concentrations of Mg (3487 ± 1250 μg g^-1 d.w.) and Zn (56.6 ± 30.1 μg g^-1 d.w.). Health risk assessments indicate that consuming conventional, agroecological, or hydroponic arugula does not pose health risks for adults. δ¹⁵N displayed similar values for conventional (8.1 ± 3.1 ‰) and agroecological systems (9.6 ± 2.9 ‰), with hydroponic arugula showing the lowest values (4.8 ± 2.7 ‰). Linear Discriminant Analysis classified arugula samples with high accuracy, particularly for hydroponic arugula (100%). These findings highlight the influence of cultivation systems on arugula's safety and quality, emphasizing the benefits of hydroponic farming for minimizing pathogen and metal contamination in leafy vegetables. Additionally, δ¹⁵N combined with multi-elemental and microbiological analyses enable a clear differentiation between hydroponic arugula and either conventional or agroecological samples.