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United States Department of Agriculture

Agricultural Research Service

Related Topics

Biothreat toxin detection
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Existing food surveillance systems are designed to detect occurrences of infections and intoxications resulting from natural contamination by microbial pathogens and the toxins produced by these organisms. This project addresses the need for validated methods to detect toxins in foods, in response to increasing concern that the intentional adulteration of food with chemical or biological agents such as bacterial and plant toxins could become a major instrument of bioterrorism. The research focuses on the detection of both crude and purified toxins and the determination of dose-response relationships. Techniques for efficient food sample preparation and new detection technologies for both laboratory and field use are also being developed. (CRIS 5325-42000-043-00D).

Toxin bioavailability – Terrorists' notebooks suggest they might try to use easy-to-prepare crude preparations of toxin to poison our food supply. We are studying the toxicity of these materials when they are diluted into food. One of our recent scientific papers on this topic is: Effect of purification on the bioavailability of botulinum neurotoxin type A

Immunochemical assays – We are creating new antibody-based tests for detection of plant and bacterial toxins in foods. Our new tests are more sensitive and more specific than existing tests, so that scientists and first-responders can obtain more information using smaller samples and fewer tests. Development and partial characterization of high-afffinity monoclonal antibodies for botulinum toxin type A and their use in analysis of milk by sandwich ELISA

Molecular Biological assays – Foods contaminated with crude preparations of protein toxins will also contain genetic material associated with the source. We are creating new tests for sensitive detection in foods of DNA associated with pathogenic bacteria (Clostridium botulinum) and poisonous plants (Ricinus communis). Detection of castor contamination by real-time PCR

Biochemical assays – Tests based on genetics (molecular biology) or antibodies (immunochemistry) will sometimes report the presence of dangerous contaminants in food, even though they have actually been rendered harmless through common food treatments, such as cooking. Tests based on the biochemical properties of toxins are not subject to such "false positives": Detection of botulinum neurotoxin-A activity in food by peptide cleavage assay


Last Modified: 3/10/2011
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