Printer Friendly

Selective enrichment medium offers simultaneous detection of bacteria.

When using a detection system, a proper selective enrichment medium is needed to detect multiple pathogens in a food sample. Currently, there is no single selective enrichment medium that can support the growth of E. coli, L. monocytogenes and Salmonella concurrently while suppressing the growth of other common food contaminants.

Researchers at Purdue University have developed a selective enrichment medium that will allow the simultaneous growth of E. coli O157:H7, L. monocytogenes and S. enteritidis for use with a suitable detection system. A selective medium designated SEL (Salmonella, E. coli and Listeria) was formulated by scientists who compared its performance with other common selective media--modified EC broth with novobiocin for E coli O157:H7, Fraser broth for Listeria, and Rappaport-Vassiliadis broth for Salmonella. The scientists used a lateral flow-based immunoassay and viable plate counting to make the comparison.

In addition, the growth of mixed cultures of E. coli O157:H7, L. monocytogenes V7 and S. enteritidis PT1 was determined in the SEL broth. Each was detected in a bacteria-specific lateral flow immunoassay strip to evaluate the ability of SEL to facilitate the detection of several foodborne pathogens simultaneously.

Each sample of E. coli O157:H7, Listeria and Salmonella grew well in SEL individually or in a mixture. The growths were comparable to those of commercially available selective enrichment broths for individual organisms. Each organism gave a strong signal in the lateral flow immunoassay after growth in the SEL. The signal was also comparable or better when grown separately in respective selective enrichment broths.

The SEL medium supported the growth of the three major foodborne pathogens individually or in a mixture and made it possible to detect each by immunoassay. This suggests that this medium, coupled with a suitable detection system, can facilitate the rapid detection of multiple pathogens concurrently from a product, thus reducing the overall cost and time of pathogen testing.

Further information. Arun Bhunia, Department of Food Science, Purdue University, 1160 Food Science Building, West Lafayette, IN 47907; phone: 765-494-5443; fax: 765-494-7953; email:
COPYRIGHT 2007 Food Technology Intelligence, Inc.
No portion of this article can be reproduced without the express written permission from the copyright holder.
Copyright 2007, Gale Group. All rights reserved. Gale Group is a Thomson Corporation Company.

Article Details
Printer friendly Cite/link Email Feedback
Publication:Microbial Update International
Date:Apr 1, 2007
Previous Article:Freeze-dried preparations of bacteriocins inhibit L. monocytogenes, S. aureus.
Next Article:Investigate the pathogen population dynamics of rice cake.

Related Articles
Piezoelectric biosensor detects seafood pathogen.
DNA sequencing speeds detection of E. coli 0157:H7.
License DNA sequencing for E. coli O157:H7.
E. coli exposed! (Innovations).
Develop new technologies that rapidly identify pathogens.
Circulating cells in cancer detection.
High pressure inactivates V. parahaemolyticus and B. cereus.
High pressure inactivates V. parahaemolyticus and B. cereus.
Competitive exclusion bacteria control Listeria.
E. coli can survive in a dormant state.

Terms of use | Privacy policy | Copyright © 2021 Farlex, Inc. | Feedback | For webmasters