The overall goal of this project is to ensure the food safety of indoor grown leafy greens by characterizing biofilms and their management, including determining their contributions to foodborne pathogen contamination. Based on our preliminary data and previous research, we hypothesize that the risk of human pathogen contamination of hydroponic leafy greens grown indoor can be reduced through the mitigation of biofilms using novel bioremediation approaches and protective cultures, without negatively impacting the plant health, its quality, and nutritional attributes.To this end we will complete the following objectives:Characterize Salmonella and Listeria monocytogenes biofilms in commercial NFT (Nutrient Flow Technology) and DWC (Deep Water Culture) leafy green indoor production systems.Evaluate the influence of algae on the establishment ofSalmonellaandListeriamonocytogeneson leafy green crops and environmental surfaces.Establishment of bioremediation procedures and alternative approaches to co-mitigation of biofilms and environmental algal mats in leafy green indoor production systems.Development of risk communication materials describing biofilm and algae management best practices in commercial NFT and DWC leafy green indoor production systems.Upon the completion of the proposed studies, we will have developed evidence-based effective food safety intervention strategies that will enable hydroponic indoor growers to ensure food safety and meet regulatory food safety requirements (FDA FSMA, Produce Safety Rule). We anticipate that much of the proposed research will have substantial near-term impacts (see Logic Model).Our work determining effective biofilm mitigation parameters will be translated into standard operating procedures usable at all spatial scales and types of growing systems in the industry. Co-mitigation practices for algae biofilms will be of huge importance to industry, and the first of its kind. We will work directly with hydroponic growers to translate our research into procedures. We will pre-test developed standard operating procedures in commercial indoor hydroponic settings.Our work will ensure that adequate sanitation practices are used by the industry, thus improving food safety of fresh produce. This is particularly important in the drive to increase consumption of nutrient dense fresh vegetables by the American public, reduce foodborne illnesses while improving nutrition and overall health. Developing new strategies to mitigate the food safety risks in hydroponics will lead to long term public health improvement and enhance the growth and sustainability of the fresh produce industry and US agriculture.