Title: Rapid, sensitive, and specific immunomagnetic separation of foodborne pathogens

Authors: Emma B. Setterington; Barbara C. Cloutier; Jessica M. Ochoa; Ashley K. Cloutier; Parul J. Patel; Evangelyn C. Alocilja

Addresses: Department of Biosystems and Agricultural Engineering, Michigan State University, 115 Farrall Hall, East Lansing, MI 48824-1323, USA. ' Department of Large Animal Clinical Sciences, Michigan State University, 115 Farrall Hall, East Lansing, MI 48824-1323, USA. ' Department of Homeland Security Minority Serving Institution, Summer Research Team, 115 Farrall Hall, East Lansing, MI 48824-1323, USA. ' 115 Farrall Hall, East Lansing, MI 48824-1323, USA. ' Department of Biosystems and Agricultural Engineering, Michigan State University, 115 Farrall Hall, East Lansing, MI 48824-1323, USA. ' Department of Biosystems and Agricultural Engineering, Michigan State University, 115 Farrall Hall, East Lansing, MI 48824-1323, USA

Abstract: Food defence requires the means to efficiently screen large volumes of food for microbial pathogens. Even rapid detection methods often require lengthy enrichment steps, making them impractical for this application. There is a great need for rapid, sensitive, specific, and inexpensive methods for extracting and concentrating microbial pathogens from food. In this study, an immunomagnetic separation (IMS) methodology was developed for Escherichia coli O157:H7, using three different types of magnetic nanoparticles (MNPs). The microbiological specificity of the IMS method was evaluated against Escherichia coli O55:H7 and Shigella boydii, and was improved by addition of NaCl during conjugation of antibodies onto MNPs. The microbiological sensitivity of the IMS method was greatest when a high concentration of antibodies (1.0 mg/ml) was present during conjugation. MNP concentrations of 1.0 mg/ml and 0.5 mg/ml provided optimal sensitivity and specificity. The entire IMS procedure requires only 35 minutes, and antibody-conjugated MNPs show no decline in performance up to 60 days after conjugation.

Keywords: foodborne pathogens; E. coli O157:H7; E. coli O55:H7; Shigella boydii; immunomagnetic separation; IMS; magnetic nanoparticles; MNPs; iron oxide; polyaniline; core nanoparticles; shell nanoparticles; specificity; monoclonal antibodies; food safety; food defence; food security; Escherichia coli; microbiological sensitivity.

DOI: 10.1504/IJFSNPH.2011.042576

International Journal of Food Safety, Nutrition and Public Health, 2011 Vol.4 No.1, pp.83 - 100

Published online: 27 Nov 2014 *