Enterobacter sakazakii (E. sakazakii) is a gram-negative food-borne pathogen, which can cause serious disease. Rapid screening plays an important role in the prevention and identification of E. sakazakii to cause food poisoning. In this study, a facile and sensitive approach for E. sakazakii detection has been presented. This novel electrochemical immunosensor based on electrochemically reduced graphene oxide-gold nanoparticles (ERGO-AuNP)/1-butyl-3-methylimidazolium hexafluorophosphate ([BMIM]PF6) was developed for the detection of E. sakazakii. Firstly, a screen-printed carbon electrode (SPCE) was modified by ERGO-AuNP. Then, the mixture of [BMIM]PF6 and HRP-anti-E. sakazakii was assembled onto the modified electrode to improve the sensitivity and selectivity of the immunosensor. The surface morphologies of modified electrodes were characterized by means of AFM and SEM. The electrochemical performance of the immunosensor was evaluated by EIS and CV. The electrochemical immunosensor for E. sakazakii exhibited a linear range from 10(3) to 10(9) CFU/mL with a detection limit of 1.19 x 10(2) CFU/mL (S/N = 3). The good performance of the immunosensor is attributed to the good biocompatibility of ERGO-AuNP films. The proposed immunosensor also exhibits excellent long-term storage stability. In addition, this electrochemical immunosensor based on ERGO-AuNP modified SPCE could also provide many potential applications for the rapid detection Of different bacteria. (C) 2015 Elsevier B.V. All rights reserved.