Signal Optimization for Salmonella Typhimurium Detection on Food Surfaces Using Phage-Based Biosensors

Abstract

This paper presents the direct detection of Salmonella typhimurium on egg shells using a phage-based magnetoelastic (ME) biosensor. The ME biosensor consists of an ME resonator as the sensor platform and E2 phage as the bio-recognition element. The bio-recognition element is genetically engineered to bind specifically with Salmonella typhimurium. The ME biosensor, a wireless sensor, vibrates with a characteristic resonant frequency under an externally applied magnetic field. Multiple sensors can easily be remotely monitored. Multiple measurement and control sensors were placed on egg shells contaminated by Salmonella typhimurium solutions with different known concentrations. The resonant frequency of sensors before and after the exposure to the spiked egg shells was measured. The frequency shift of the measurement sensors was significantly different than the control sensors indicating Salmonella contamination. Scanning electron microscopy was used to confirm binding of Salmonella to the sensor surface and the resulting frequency shift results.