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Sono-chemical signal developmemt as a novel generic methods for the rapid, in situ and specific detection of - FS1245

low levels of food hazards at line
1. Nanoparticulate enzyme Enzyme preparations will be aggregated into small particles, considering (bi-functional cross-linking) physicochemical (precipitation), biochemical (streptavidin) and physical (dielectrophoretic, ultrasonic) methods. The quality of particles (size, polydispersity) will be monitored by dynamic light scattering (photon correlation and diffusing wave spectroscopies) and by assay of their relative activities. 2. Selection of sonochemical system Sonochemical reaction systems will be reviewed and selected according to their suitability for signal generation in food matrices and their ability to incorporate into particle systems in a robust and stable manner. 3. Lipid coating of nanoparticulate enzyme A procedure will be developed to coat the nanoparticulate enzyme with a lipid-based layer to block permeability. Sizes, poldisopersities, concentrations, physical and biological stability's will be similarly determined. Particular attention will be devoted to attaining low background activity and high stability under normal storage and storage and treatment conditions (pH, saly etc). Practical estimates will be made of the number of particles required to produce detectable vapour on activation by low numbers of microorgansims. 4. Formulation of particulate sonochemical system The sonschemical system selected will be produced as a monodisperse sun-micron particle suspension which can be incorporated into the responsive particle system. 5. Specifically triggered vapour production Our new peptide based biotin amplified system developed for lipsomes will be incorporated into the lipid coated nanoparticle system. Coated manoparticles will be modified with available antibodies for the pathogens so that activity is triggered on binding of the nanoparticle. Practical estimates will be made of the triggering efficiency and stability compared to the number and stability required for useful measurement. 6. Incorporation of sonochemistry into responsive particle Related methods will be developed to incorporate the sonochemistry into the responsive lipid coated system. 7. Demonstration of vapour and sonochemical signal detection System to detect vapour and sound will be established and used to compare signal development on triggering. 8. Specific microbiological hazard detection Known low number concentration of pathogen will be seeded into various model media and matrices and the vapour production and/or sound generation monitored, compared to controls and the count of organisms (where possible by present methods ie>10/ml, otherwise relying on known addition and back extrapolation of growth curves). behaviour will be considered in non-growing suspension, defined media, complex growth media, homogenised food plus growth and homogenised food. 9. Hazard detection on film for packaging Colour chemistry for dosimetric of vapours on plastic film will be developed and applied to detecting specific vapour production on the presence flow numbers of microorganisms and compared to controls. PiezOptical detection of colour development on PVDF film will be evaluated. 10. Evaluation for at/on line hazard detection The performance of vapour and sonochemical detection will be optimised and evaluated to enable comparison of their potential in microbiological hazard detection, as a rapid screening method in the laboratory, near real time monitoring at or on line and for revealing potential hazard in packaged food.
Time-Scale and Cost
From: 1996

To: 1999

Cost: £346,035
Contractor / Funded Organisations
University - Manchester