Sensor detection of shelf life: a multi-technique food analytical platform for mushroom analysis

Food quality and safety have always been major concerns worldwide, impacting directly the lives of millions of people. Our study aims to propose an innovative approach to differentiate freshly packaged Agaricus bisporus mushrooms from expired Agaricus bisporus using a graphene field-effect transistor (GFET) sensor. Commercial samples analyzed with GFET sensor demonstrated distinct electrical current measurements, presenting a difference of nearly one order of magnitude between fresh and expired groups. Results obtained with the device are considered promising and are attributed to the innovative layout adopted for the graphene channel structure in the GFET, which enabled direct contact between the analyte and the titanium dioxide (TiO₂) surface. Protonation and deprotonation processes were possible due to such interactions between the analyte and the GFET sensor surface, which in turn led to the release and capture of electrons, modulating the device electrical outputs, according to the analyzed sample. Sensor performance was corroborated by Fourier-transform infrared (FTIR) spectroscopy and ultra-high-resolution mass spectrometry (UHRMS) techniques. FTIR analysis revealed subtle spectral differences between fresh and expired samples, particularly in protein and carbohydrate regions. UHRMS analysis enabled the identification of differentiating compounds, including sugars, nucleotides, peptides, and fungal contaminants, providing molecular insights into changes that led to expiration after storage. This novel approach boasts potential to enhance the predictability of shelf life in fresh products, which may contribute to promote food waste reduction, as well as to assist in decision-making processes to put food safety measures into place.