<p> A disposable graphite pencil electrode (GPE)-based electrochemical biosensor for the detection of aflatoxin B1 (AFB1) in milk samples is presented. The biosensor surface was functionalized with a ternary nanocomposite comprising graphene oxide nanoribbons (GONRs), MXene (Ti₃C₂T_<i>x</i>), and silver nanoparticles (Ag NPs). The ternary nanocomposite-modified GPE surface was further modified with a functional molecule (polyethylene glycol, PEG) to enhance biocompatibility and facilitate antibody immobilization. The resulting biosensor, anti-AFB1/PEG/Ag@GONRs/MXene/GPE, exhibited high sensitivity toward AFB1 due to the synergistic effects of its components—large surface area and active sites of MXene, abundant edge functionalities of GONRs, and excellent conductivity of Ag NPs. The immunosensor demonstrated a strong electrochemical response in phosphate-buffered saline (PBS) over a concentration range 1–100 pg mL⁻¹, achieving a low limit of detection (LOD) of 0.8 ± 0.40 pg mL⁻¹. Its performance was further validated in spiked milk, maize, peanuts, oil samples and naturally contaminated betel nuts samples, achieving high recoveries and demonstrating its strong potential for practical applications in food-safety monitoring.</p> Graphical abstract <p></p>