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United States Department of Agriculture

Agricultural Research Service

Research Project: INTEGRATED BIOSENSOR-BASED PROCESSES FOR MULTIPATHOGENIC ANALYTE DETECTION

Location: Molecular Characterization of Foodborne Pathogens

Title: Detection of Salmonella Enteriditis from egg components using different immunomagnetic beads and time–resolved fluorescence

Authors
item Tu, Shu-I
item Reed, Sue
item He, Yiping
item Gehring, Andrew

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: March 15, 2008
Publication Date: May 15, 2008
Citation: Tu, S., Reed, S.A., He, Y., Gehring, A.G. 2008. Detection of Salmonella Enteriditis from egg components using different immunomagnetic beads and time–resolved fluorescence. [Abstract]p.2-42.

Technical Abstract: The types of chemical linkage used to link antibodies to magnetic beads to form immunomagnetic beads (IMB) were compared in the capture and detection of Salmonella Enteriditis from egg components. Egg components were inoculated with outbreak strains of S. Enteriditis. After incubation under different conditions, IMBs derived from linking antibodies to core magnetic beads via biotin-streptavidin interactions, Schiff-base bonds and unspecified proprietary chemistry were used to capture S. Enteriditis. Europium-labeled anti-Salmonella antibodies completed the sandwich, and time-resolved fluorescence served as the means of detection. For the Salmonella cultured from UPB, the detection signal intensity was affected by the chemistry utilized to link the antibodies to IMB. Relative to UPB, much lower detection signals were detected in cultures obtained from egg components. Egg yolk proved to be as good as UPB in supporting the growth of S. Enteriditis, but not egg white. For cultures obtained from egg yolks, the low detection signals by all IMBs suggesting the accessibility of the antigenic groups to the antibodies on IMBs was reduced. The addition of UPB to egg white restored the growth of Salmonella and yielded stronger detection signals than from cultures obtained from UPB with egg yolk. For the same cultures, the detection signal intensity obtained by different IMBs varied considerably. The results suggested that the intensity of detection signal was affected by the linking mechanism used for conjugating the antibodies to the magnetic beads. Presumably, the linkage might affect the interactions of the antibodies to the antigenic groups on the bacteria.

Last Modified: 8/22/2014
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