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A Portable Impedance Aptasensing System for Rapid Detection of Salmonella Typhimurium in Poultry Products

Published by the American Society of Agricultural and Biological Engineers, St. Joseph, Michigan

Citation:  2018 ASABE Annual International Meeting  1801147.(doi:10.13031/aim.201801147)
Authors:   America F Sotero, Ronghui Wang, Wen Tao, Benhua Zhang, Yanbin Li
Keywords:   Impedance aptasensor, portable system, rapid detection, Salmonella Typhimurium

Abstract. Each year, Salmonella Typhimurium causes an estimated 19,000 hospitalizations and 380 deaths in the US. It is considered one of the most dangerous foodborne pathogens and a major threat to human health. Therefore, there is an urgent need for the development of a rapid and reliable method to detect Salmonella in food products. The goal of this project was to develop a portable impedance aptasensing system using an interdigitated microarray electrode (IDME) for the rapid and sensitive detection of S. Typhimurium in poultry products. In this study, the IDME was functionalized with 16-Mercaptohexadecanoic acid followed by surface immobilization with NH2-aptamer specific to S. Typhimurium. Poly (ethylene glycol) methyl ether thiol was used for surface blocking following aptamer immobilization. The IDME was then left to rest for 48 h at room temperature to be ready for use in tests. After sample preparation, 50µl of the sample containing S. Typhimurium was dropped onto the IDME‘s surface which allowed the immobilized aptamer to capture the Salmonella cells. The impedance change caused by the capture of target bacterial cells was measured in the presence of a redox probe and recorded using a laptop with LabVIEW software. The results showed that there was a linear relationship with a correlation coefficient of 0.95 between the impedance change and the log value of S. Typhimurium in a range of concentrations from 1.41x101 to 1.41x105 CFU/50 μl in pure culture samples. The total detection time from sampling to final results was less than one hour. The developed impedance aptasensor has limit of detection (LOD) of 7.39%, or 1.14x101 CFU/50 µL of S. Typhimurium in pure culture, as well as being highly specific to S. Typhimurium. On-going research is focused on testing S. Typhimurium in poultry products using a flow cell imbedded with the IDME immobilized with aptamers. Due to its shorter detection time, low cost, and LOD, the developed aptasensor has the potential to improve in-field or at-line detection of foodborne pathogens.

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