Microbial Quality of Leafy Greens Grown Under Soilless Production Systems

This review examines the microbiological diversity and food safety implications of soilless production systems, particularly aquaponics and hydroponics, which are gaining popularity as efficient methods for producing fresh produce in controlled environments. Despite their advantages, a limited understanding of the microbiological quality and potential food safety risks associated with leafy greens grown in these systems remains. By analyzing published studies, we summarize evidence of microbial contamination in aquaponic and hydroponic environments and their crops, noting that various factors may facilitate pathogen survival and spread to edible plant parts. The operational practices and environmental conditions can promote pathogen introduction through multiple routes, including contaminated fingerlings, fish feed, recirculating contaminated water, pest intrusion, improper handling, and poor worker hygiene. The studies reviewed detected pathogens that pose public health risks, including Salmonella spp., Listeria monocytogenes, Pseudomonas aeruginosa, and Shiga toxin-producing Escherichia coli O157:H7, as well as various molds. These potentially contaminated fresh produces are often consumed raw, presenting significant food safety and public health risks that demand further investigation and mitigation strategies to ensure consumer protection while maintaining the benefits of soilless agriculture.