Two-stage label-free aptasensing platform for rapid detection of Cronobacter sakazakii in powdered infant formula

Abstract

Cronobacter sakazakii constitutes one of the most life-threatening foodborne pathogens in neonates, and is typically acquired via contaminated powdered infant formula. In this study, we developed a sensitive and convenient two-stage label-free aptasensing platform for colorimetric detection of C. sakazakii in powdered infant formula. In this system, C. sakazakii depletes aptamers from the test solution, and the reduction of aptamers induces aggregation of gold nanoparticles in salt, a process accompanied by a color change from red to purple. Under optimal conditions, C. sakazakii present in PIF at a concentration as low as 7.1 x 10(3) CFU mL(-1) could be visually detected within 30 min, with a linear range between 7.1 x 10(3) and 7.1 x 10(7) CFU mL(-1). This novel assay provides new opportunities to detect bacteria in real-world samples.