Hydroponics is a farming technique for growing plants with mineral nutrients using a soil-free medium. The plant roots are submerged in soil-free media, such as vermiculite or perlite, or just in mineral nutrient solutions. This allows for high production yields throughout the year with less water and agro-chemical inputs. Consequently, hydroponics is considered a sustainable agriculture technology. Hydroponically grown crops are usually protected from the diseases transmitted through soil or animals in open fields. Therefore, they require fewer chemicals for pest control and are safer than conventionally grown crops in terms of possible chemical contamination. Nevertheless, hydroponics guarantees neither plant health nor the microbial safety of fresh produce. In the case of microbial contamination by human pathogens, unlike soil-grown crops, the pathogens may rapidly spread through the circulating water and simultaneously infect all the plants in the facility. This review summarizes the up-to-date knowledge regarding the microbial safety of hydroponically grown crops and discusses the role of the hydroponic system in reducing the microbial hazards for leafy and fruity crops as well as the potential risks for contamination by human pathogens. Finally, it outlines the approaches and the available science-based practices to ensure produce safety. The contamination risk in hydroponic systems may be diminished by using novel planting materials and the appropriate decontamination treatment of a recirculating liquid substrate; by modulating the microbiota interactions; and by following strict phytosanitary measures and workers’ hygienic practices. There is a timely need to adopt measures, such as the Good Agricultural Practice (GAP) guidelines, to mitigate the risks and ensure safe hydroponically grown vegetables for consumers.

Curcumin has been known for a long time for its antimicrobial properties that are further increased by exposure to light. Due to the low aqueous solubility of curcumin, appropriate delivery systems are required to facilitate its implementation. In this work, we compared the antimicrobial activity toward Escherichia coli of two curcumin formulations: methyl-β-cyclodextrin supramolecular inclusion complex and polyelectrolyte-coated monolithic nanoparticles. The two formulations showed disparity both in the extent and in the mode of toxicity, highlighting the distinct properties of materials at the nanoscale. The tests showed that while curcumin–β-cyclodextrin complexes exhibited a potent bactericidal activity, the curcumin nanoparticles were bacteriostatic. Illumination with blue light significantly increased the bactericidal efficacy of curcumin–cyclodextrin complexes but had limited influence on the activity of nanoparticulate curcumin. While the antimicrobial effect of the supramolecular complex was predominantly characterized by the increase in ROS and inhibition of electron transport, the primary attributes of the nanoparticle action were membrane depolarization and reduced ATP concentrations. Interestingly, the treatment with curcumin nanoparticles induced a filamentous phenotype of the bacterium. Our results suggest that the antimicrobial properties of curcumin depend upon a delivery formulation, which may have both practical and regulatory implications on the applicability and safety of curcumin nanomaterials.

Summer savory (Satureja hortensisL.,Lamiaceae) is used in several regions of the world as a spice and folk medicine. Anti-inflammatory and cytoprotective effects ofS. hortensisand of its rosmarinic acid-rich phenolic fraction have been demonstrated in animal trials. However, previous studies of rosmarinic acid in cell models have yielded controversial results. In this study, we investigated the effects of summer savory extracts on H₂O₂-challenged human lymphoblastoid Jurkat T cells. LC-MS analysis confirmed the presence of rosmarinic acid and flavonoids such as hesperidin and naringin in the phenolic fraction. Adding 25 or 50 µM of H₂O₂to the cell culture caused oxidative stress, manifested as generation of superoxide and peroxyl radicals, reduced cell viability, G0/G1 arrest, and enhanced apoptosis. This stress was significantly alleviated by the ethanolic and aqueous extracts ofS. hortensisand by the partially purified rosmarinic acid fraction. The application of an aqueousS. hortensisextract doubled the activity of catalase and superoxide dismutase in the cells. The production of IL-2 and IL-10 interleukins was stimulated by H₂O₂and was further enhanced by the addition of theS. hortensisextract or rosmarinic acid fraction. The H₂O₂-challenged Jurkat cells may serve as a model for investigating cellular mechanisms of cytoprotective phytonutrient effects.