Development of mitigation strategies toward preventative postures in food defense.

摘要

od defense is a multidisciplinary study. The body of this work is divided into a case control study on terrorism organizations and the development of a food based testing platform for detection of food based terrorism agents. To begin, few terrorism studies have explored the factors that distinguish groups that will use Chemical, Biological, Radiological or Nuclear (CBRN) terrorism involving the food supply. Ethno-separatist ideology, increased cultural embeddedness within the global culture, increased connectedness to other organizations and democratic regime type all show significant results as predictors of food based CBRN attacks by an organization (p = 0.1). Food defense requires the means to efficiently screen large volumes of food for microbial pathogens. Even rapid detection methods often require lengthy enrichment steps, making them impractical for this application. There is a great need for rapid, sensitive, specific, and inexpensive methods for extracting and concentrating microbial pathogens from food. A carbohydrate coated screen printed carbon electrode (D-FSPCE) was evaluated as a sensitive platform for multiplex evaluation of food samples extracted by immuno-magnetic separation (IMS) with electrically active magnetic nano-particles (EAMNPs). These nanoparticles provide the selectivity of the biosensor through their attached monoclonal antibody (Mab) while the carbohydrate coated chips provide the nonselective, shelf stable electrical detection platform. When combined, the D-FSPCE + Mab-EAMNP, using cyclic voltammetry for an electrical readout, are named the M 3 Biosensor. In this body of work, methodology was optimized for Escherichia coli O157:H7. The analytical specificity of the 40 minute IMS method was improved over previous protocols by addition of sodium chloride and a higher concentration of antibodies (1.0 mg/mL) during the conjugation of antibodies onto MNPs. EAMNP concentrations of 1.0 mg/mL and 0.5 mg/mL provided optimal analytical sensitivity and analytical specificity as potential concentrations for the evaluation of food substances with no statistical difference between them. Antibody-conjugated EAMNPs show no decline in performance up to 149 days after conjugation with a capture efficiency of 92% all the way down to 5 CFU/mL; equivilant to a widely used commercial IMS methodolgy. The EAMNP portion of the M3 Biosensor can also capture and detect bacterial cells down to 1-4 MPN/mL from 200 mL of whole fluid milk in 1 hour, without pre-enrichment. The extraction protocol's inclusivity within strain is 94% and exclusivity outside the E. coli O157 family is 87%. The second half of the M3 Biosensor is the D-FSPCE and statistically significant qualitative (presence/absence) differentiation (p = 0.0015, n = 188) can be performed from broth from 100 CFU/mL to 1.0 *108 CFU/mL. Additionally, 39 organisms of 10 bacterial genera in both gram stain groupings all attached to the carbohydrate coated D-FSPCE, allowing for this platform to be used with many other organisms. M3 Biosensor has electrical chemical detection with statistically significant differences as low as 5 CFU/mL and a signal to noise ratio of 2:1, in broth. A linear range of 5 CFU/mL to 1.0 *108 CFU/mL for both IMS analysis and CV analysis is excellent performance through over 200 repeat analyses at a cost for one sample of