Food safety is a growing concern due to frequent contamination. For the first time, this study introduces a novel cylindrical SERS substrate using copper rods (CuR) with electroless deposited silver nanoparticles (AgNPs) and a graphene oxide (GO) coating for efficient food monitoring. The GO/AgNPs/CuR substrate enhances signals through dense “hot spots” and superior analyte adsorption, achieving a low detection limit of 2.07 × 10⁻¹ ⁰ M for erythrosin B (ErB) with an enhancement factor of 5.19 × 10⁸. It offers excellent uniformity (RSD 7.77 %) and retains 71 % efficiency after 18 days. Notably, it detected ErB in pink fennel seed candy without spiking and achieved 85.4–97.2 % recovery in white fennel seed candy at 10⁻¹ ⁰ M. With simple fabrication, high sensitivity, and demonstrated applicability, this GO/AgNPs/CuR SERS substrate is a promising tool for real-world food safety inspection.