title: Detection of pathogenic bacteria in food samples using highly-dispersed carbon particles.
abstract: There is an unmet need for detection methods that can rapidly and sensitively detect food borne pathogens. A flow through immunoassay system utilizing highly dispersed carbon particles and an amperometric technique has been developed and optimized. A sandwich immunoassay format was utilized in which pathogenic cells were captured by antibodies immobilized onto activated carbon particles, and labeled with horseradish peroxidase (HRP) conjugated antibodies. Flow of the peroxidase substrates resulted in an amperometric signal that is proportional to the number of captured cells. Factors influencing the analytical performance of the system, such as the quantity of carbon particles and concentrations of capture antibody, enzyme labeled antibody, and enzyme substrates, were investigated and optimized. Detection and quantification of Escherichia coli, Listeria monocytogenes and Campylobacter jejuni were demonstrated with low detection limits of 50, 10, and 50 cells/ml, respectively, and an overall assay time of 30 min. Milk and chicken extract samples were spiked with various concentrations of these pathogens and were used to challenge the system. The system design is flexible enough to allow its application to the detection of viruses and proteins.
authors.affiliation: Department of Chemical and Nuclear Engineering, University of New Mexico, 209 Farris Engineering Center, Albuquerque, NM 87131, USA.
authors.forename: Sireesha
authors.initials: S
authors.lastname: Chemburu
authors.forename: Ebtisam
authors.initials: E
authors.lastname: Wilkins
authors.forename: Ihab
authors.initials: I
authors.lastname: Abdel-Hamid
mesh_terms: D001419:Bacteria / Q000201:enzymology / Q000276:immunology / Q000302:isolation & purification*; D015374:Biosensing Techniques / Q000295:instrumentation* / Q000379:methods; D002244:Carbon / Q000737:chemistry*; D020099:Coated Materials, Biocompatible / Q000737:chemistry; D015169:Colony Count, Microbial / Q000295:instrumentation* / Q000379:methods; D004867:Equipment Design; D019544:Equipment Failure Analysis; D017022:Flow Injection Analysis / Q000295:instrumentation / Q000379:methods; D005504:Food Analysis / Q000295:instrumentation / Q000379:methods; D005506:Food Contamination / Q000032:analysis*; D005516:Food Microbiology; D006735:Horseradish Peroxidase / Q000032:analysis / Q000276:immunology; D007118:Immunoassay / Q000295:instrumentation* / Q000379:methods; D010316:Particle Size
chemical_list: D020099:Coated Materials, Biocompatible; D002244:Carbon; D006735:Horseradish Peroxidase