Pathogens biosensor-based detection methods

Seo et al. (1999) used a planar optic biosensor that measures the phase shift variation in refractive index due to antigen binding to antibody. In this method, they were able to detect S. enterica serovar T) himurium with a detection limit of 1 x 10 cfu/ml. When chicken carcass fluid was inoculated with 20 cfu/ml, the sensor was able to detect this pathogen after 12 h of nonselective enrichment. A compact fiber optic sensor was also used for detection of S. T) himurium at a detection limit of 1 X 10" cfu/ml (Zhou et al., 1997, 1998) however, its efficacy with food samples is unproven. Later, Kramer and Lim (2004) used the fiber optic sensor, RAPTOR , to detect this pathogen from spent irrigation water for alfalfa sprouts. They showed that the system can be used to detect Salmonella spiked at 50 cfu/g seeds. An evanescent wave-based multianalyte array biosensor (MAAB) was also employed for successful testing of chicken excreta and various food samples (sausage, cantaloupe, egg, sprout, and chicken carcass) for S. T) himurium (Taitt et ah, 2004). While some samples exhibited interference with the assay, overall, the detection limit for this system was reported to be 8 x 10 cfu/g. 

Devices that can be used by an individual without medical supervision (for example, biosensors incorporated in a bandage) need to be developed to detect and identify hnman exposure to chemical and biological agents. Current methods nsed to connteract hnman exposure to pathogens involve needle-based drug... 

The barcodes have been primarily used to assure brand and authenticity in pharmaceuticals, but applications could be forthcoming in tracing food batches. Combined with pathogen sensors, the barcodes that must be read by modified microscopes could trace sources of outbreak. There are antibacterial surfaces for the machines involved in food processing or production. With the conventional methods of detection it takes hours to days. With molecular electronic based methods, biosensors, e-nose, microarrays, nanobiosensors (based on microfluidic, nanomaterials, DNA, etc.) it takes seconds to minutes. A biosensor developed by an Agricultural Research Service scientist, Athens, uses fluorescent dye particles attached to bacteria antibodies. If Salmonella bacteria are present in the food being tested, the nanoculturing results with these two examples of instantaneous sensors, sized dye particles become visible. No need to send out to the lab and wait days for results. 

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