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Assay to Detect and Quantify E. Coli O157 in Water Samples


Phase I SBIR proposals will be accepted. Fast-Track proposals will not be accepted. Phase I clinical trials will be accepted. Number of anticipated awards: 1-2 Budget (total costs): Phase I: up to $150,000 for up to 6 months PROPOSALS THAT EXCEED THE BUDGET OR PROJECT DURATION LISTED ABOVE MAY NOT BE FUNDED. Background Current methods for detecting and quantifying E. coli in water samples do not detect E. coli O157 or other related Shiga toxin-producing E. coli (STEC) strains. There are several commercially available assays to quantify E. coli in water samples; however, they rely on detection of the beta-glucuronidase enzyme, which is not present in STEC strains. Food Safety and Modernization Act (FSMA) regulations now require food producers to ensure that all water used for irrigation meet the standards for recreational water, which sets a maximum value at 126 cfu/100 ml. Despite this regulation, a multistate outbreak of E. coli O157 was linked to contaminated irrigation water used for romaine lettuce production. The outbreak strain was isolated from three irrigation water samples. Importantly, all three of these samples were below the FSMA-required E. coli levels, suggesting that even water that passes standard water quality metrics can harbor dangerous levels of E. coli O157. Project Goals The goal of the proposed research is to develop an assay that can detect and quantify E. coli O157 in water samples. This assay must be amenable to on-site use by stakeholders, such as farm managers, environmental health consultants, water managers, and packing shed managers. The assay can use molecular or non-molecular methods to detect and quantify E. coli, but must not require an advanced molecular laboratory. The assay will provide a quantitative measure of E. coli O157 present in the sample and must be able to detect 1 cfu/100 ml. Phase I Activities and Expected Deliverables The expected deliverables are: 1. Develop or adapt a method to detect and quantify E. coli O157 in water samples; the assay must be able to detect 1 cfu/100 ml. 2. Determine the sensitivity and specificity of the test against E. coli O157, other STEC serotypes, and non-STEC E. coli. 3. Conduct matrix evaluation to understand the assay performance using different water types (e.g., varied mineral or chemical composition, pH, etc. of the water source being tested). Impact The product of this proposed research will allow food producers to monitor their water supplies for E. coli O157, which is currently not possible. Once monitoring is available, control processes can be implemented to protect food products and ultimately reduce the burden of E. coli O157 infections. Commercialization Potential This research will lead to the development of a new water quality test method that can be implemented by stakeholders at every point in the supply chain from the farm to the packing shed operators. Potential products include assay kits, assay reagents, and water sampling devices. These products could be used by farm managers, water managers, and packing shed operators, as well as federal, state, and local public and environmental health agencies
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