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Title: SIMULTANEOUS AND RAPID IDENTIFICATION OF ESCHERICHIA COLI, LISTERIA MONOCYTOGENES, AND SALMONELLA TYPHIMONIUM BY SURFACE-ENHANCED RAMAN SCATTERING SPECTROSCOPY

Author
item LIU, YONGLIANG - VISITING SCI, UMCP
item CHEN, YUD-REN - RETIRED-USDA/ARS/BA/ISL
item Nou, Xiangwu
item Chao, Kuanglin - Kevin Chao

Submitted to: BARC Poster Day
Publication Type: Abstract Only
Publication Acceptance Date: 4/25/2007
Publication Date: 4/25/2007
Citation: Liu, Y., Chen, Y., Nou, X., Chao, K. 2007. Simultaneous and rapid identification of escherichia coli, listeria monocytogenes, and salmonella typhimonium by surface-enhanced raman scattering spectroscopy. BARC Poster Day, Beltsville, MD, April 25, 2007.

Interpretive Summary:

Technical Abstract: The development of rapid and routine identification methods for foodborne bacteria is of considerable importance due to concerns regarding bio-/agro-terrorism, public health, and economic loss. The traditional techniques are time consuming and are not sufficiently rapid to assure the safety of ready-to eat products. Recently developed biosensors for rapid and specific detection of bacteria tend to have time requirements and rates of false negatives/positives that limit their usefulness for rapid detection of bacteria. Fast microbial detection requires minimal sample preparation, permits the routine analysis of large numbers of samples with negligible reagent costs, and must be easy to operate. We have developed silver colloidal nanoparticle based surface-enhanced Raman scattering (SERS) spectroscopy as a potential tool for the rapid and routine detection of specific bacteria. This method has several outstanding merits: (1) silver nanoparticle colloids are easy and inexpensive to prepare and their lifetime has been found to be much longer than that of vacuum-deposited nanoparticle films, (2) incubated bacterial cultures are directly mixed with silver colloids in tubes, requiring no purification, separation, drying procedures and also reducing the likelihood of cross-contamination, (3) characteristic band based simple algorithms are more useful in determining bacterial species, and (4) SERS spectral collection and data interpretation can be completed in timeframes as short as 5 min. This study presents the recent results of our examination of the method for different bacterial species and reveals the usefulness of intense and unique SERS bands for the simultaneous identification of Escherichia coli, Listeria monocytogenes, and Salmonella typhimonium cultures. Since scanning one sample took 5~6 min and a minimum of 50 mL colloid/culture mixture was used, silver colloidal nanoparticle based SERS could be used in routine, rapid, qualitative, and simultaneous screening of Escherichia coli, Listeria monocytogenes, and Salmonella typhimonium cultures on a large scale.