Detection of Salmonella Enterica Serovar Typhimurium in Alfalfa Sprouts by Using a Rapid Array Based Immunosensor

Detection of Salmonella enterica Serovar Typhimurium by Using a Rapid, Array-Based Immunosensor

Applied and Environmental Microbiology, January 2004, p. 152-158, Vol. 70, No. 1

Chris Rowe Taitt,1* Yura S. Shubin,2 Roselina Angel,3 and Frances S. Ligler1

Center for Bio/Molecular Science and Engineering, Naval Research Laboratory, Washington, D.C.,1 GeoCenters, Suitland,2 Department of Poultry Science, University of Maryland, College Park, Maryland3



The multianalyte array biosensor (MAAB) is a rapid analysis instrument capable of detecting multiple analytes simultaneously. Rapid (15-min), single-analyte sandwich immunoassays were developed for the detection of Salmonella enterica serovar Typhimurium, with a detection limit of 8 x 104 CFU/ml; the limit of detection was improved 10-fold by lengthening the assay protocol to 1 h. S. enterica serovar Typhimurium was also detected in the following spiked foodstuffs, with minimal sample preparation: sausage, cantaloupe, whole liquid egg, alfalfa sprouts, and chicken carcass rinse. Cross-reactivity tests were performed with Escherichia coli and Campylobacter jejuni. To determine whether the MAAB has potential as a screening tool for the diagnosis of asymptomatic Salmonella infection of poultry, chicken excretal samples from a private, noncommercial farm and from university poultry facilities were tested. While the private farm excreta gave rise to signals significantly above the buffer blanks, none of the university samples tested positive for S. enterica serovar Typhimurium without spiking; dose-response curves of spiked excretal samples from university-raised poultry gave limits of detection of 8 x 103 CFU/g.