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Identification of novel indicator organisms to determine the risks of fecal contamination of irrigation waters


"The methods used to detect E. coli were developed for drinking water and are known to produce high levels of false-positive and false-negative results when used for irrigation waters. Therefore, growers are required to make decisions about water quality/safety based on inaccurate tests. Our project goal is to identify microorganisms which may be used as novel indicators of the presence of pathogens (not just fecal contamination) in irrigation waters to allow the produce
industry to make more accurate risk-based assessments to determine when it is safe to irrigate crops. Our specific objectives are the following: 1) We will examine irrigation water to determine the levels of fecal indicator and pathogenic bacterial/viral species by existing cultural and/or molecular methods; 2) We will determine the composition (presence and relative abundance) of the entire bacterial, protozoan, and fungal communities found in irrigation water using “nextgeneration”
sequencing; 3) We will identify groups or specific species whose presence correlate well (presence/absence and relative abundance) with the occurrence of foodborne pathogens in irrigation waters. The use of more meaningful indicator species will provide growers with more accurate information upon which to optimize their irrigation practices to minimize the risk of contamination of produce by foodborne pathogens."

Bright, Kelly; Ikner, Luisa
University of Arizona
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