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Abstract
Biofilms are known to form inside irrigation distribution lines to the point of complete blockage from the emitter holes. However, there is inadequate understanding of how foodborne pathogens may survive and what role biofilm formation may play in these conditions. The long-term objective of this research was to determine if irrigation lines can be a significant source of pathogens and not simply the source water which has been the primary focus by industry, policy makers, and researchers. Therefore, the objectives were to first, determine the microbial communities present within different irrigation water distribution lines in southern Georgia. Second, to evaluate the behavior of Salmonella in an irrigation drip tube system and its ability to form biofilms at different water quality parameters. Third, to evaluate control measures to prevent biofilm formation within the irrigation drip tubes. For objective one, swab samples were taken from different irrigation distribution lines (n=6 drip and n=2 center pivot). Samples were then processed for 16S rDNA sequencing for genome identification and operational taxonomical classification. For both the second and third objectives, drip tubes with no perforations were filled with surface water inoculated with a four-serotype cocktail rifampicin resistant Salmonella, under different fertigation and chemigation parameters. Populations in the water and attached to the tubing were determined overtime. This study characterized the temporal and spatial dynamics of microbial communities in irrigation distribution systems used for fruit and vegetable production across various configurations, investigated the role of the foodborne pathogen Salmonella and biofilm development in response to commonly injected fertilizers in organic and conventional systems, and evaluated the efficacy of commonly used sanitizers in inactivating Salmonella biofilms within an irrigation line. These findings provide critical insights for improving irrigation system management and enhancing food safety practices in agricultural production