New Research at the USDA ARS on Detection of Crude Botulinum Neurotoxin in Food

1. Scenario: adulteration of liquid egg, ground meat, milk Foods contain fats, flavonoids, and other components that can interfere with assays. These agricultural commodities are particularly at risk during storage and transport. Compared to purified BoNT (150kDa), crude toxin complex (900kDa) is more stable and has greater oral bioavailability. Bioterrorism may involve intentional adulteration with a crude preparation of toxin. 3.0 Mechanism-based assays for specificity Immunochemical assays for robustness and high sensitivity 2.5 2.0 1.5 1.0 0.5 0 1 10 100 1 Research goals Optimize sample preparation for assays of crude toxin in food. Novel immunoassay/immunosensor format: bead, nanoparticle, array, “black box.” Cell culture assay for high throughput with biological relevance Novel ex vivo format: cell culture, transfected/engineered host. Measure immunoprotection after oral exposure to crude toxin. Examine possibility of synergy between BoNT and Shigatoxin or ricin. New Research at the USDA ARS on Detection of Crude Botulinum Neurotoxin in Food John Mark Carter, Ron Binder, Larry Stanker, David Brandon USDA Agricultural Research Service, Western Regional Research Center, Albany, CA (www.ars.usda.gov/pwa/wrrc/fcr) Assay validation for crude toxin in food matrices Fluorescence Toxin (ng/ml) Toxin complex includes surrogate analytes. Development and validation of novel assays Non-toxic accessory proteins provide surrogate analytes. Compared to BoNT (150kDa), these surrogates may exhibit increased immunogenicity, improved stability in food, enhanced assay sensitivity, and simplified sample preparation. Zhou, et al, 2005, FEBS J, 272:2717 Rodent model for standardization