The design, simulation, fabrication, and characterization of a highly sensitive double-layer coil detector, utilized with magnetoelastic (ME) biosensors to detect bacterial pathogens, is presented in this paper. The former coil detector was a single-layer coil employed to realize wireless Salmonella detection on various food surfaces, while the double-layer coil in this work has enhancement in sensor excitation and detection sensitivity. With the double-layer coil, not only the wireless detection distance can be further, but also a smaller ME biosensor can be used in the detection to provide higher mass sensitivity. Various coil design parameters, including the thickness of layers, width, height, and spacing of coil turns, were studied. Both theoretical calculations and experimental data showed that the above parameters have a significant impact on the signal amplitude and stand-off distance. Finally, with the newly fabricated double-layer coil detector, detection of Salmonella Typhimurium using multiple biosensors on a food grade Ultra-high-molecular-weight polyethylene (UHMW-PE) board surface was demonstrated. This double-layer coil detector, therefore, facilitates the detection of pathogens on food and food contact surfaces.