Rapid detection of Salmonella typhimurium in food samples using a bienzyme electrochemical biosensor with flow injection

摘要

A bienzyme (tyrosinase and horseradish peroxidase) electrochemical biosensor was developed for detection of Salmonella typhimurium, and evaluated for application in a flow injection system coupled with immunomagnetic separation for food samples. Parameters for immunomagnetic separation, enzymatic reaction, flow injection and electrochemical detection were determined using pure culture samples. The selectivity was tested in the presence of Listeria monocytogenes, Campylobacter jejuni and E. coli O157:H7. The results showed a linear relationship for logarithmic values between peak current ratio and the cell number of S. typhimurium in the range of 10(3) similar to 10(5) cfu/mL, with R-2 = 0.99. The detection limit of this method was 1.09 x 10(3) cfu/mL for S. typhimurium and the detection time was 2.5 h. Samples of chicken carcass wash water and ground beef were used to evaluate the biosensor. The results demonstrated that this biosensor has a potential for rapid detection of different pathogens in various food samples.