Designing an intelligent nanofiber ratiometric fluorescent sensor sensitive to biogenic amines for detecting the freshness of shrimp and pork

The low sensitivity of fluorescent sensors limits the on-site and visual detection of seafood freshness. To address these issues, a novel intelligent nanofiber ratiometric fluorescent sensor, known as a BAsCNF, was designed using cellulose nanofibers (CNFs) produced by TEMPO oxidation (TO-CNFs) as the skeleton, and fluorescein isothiocyanate and proporphyrin IX modified nanofibers as the indicator and internal reference, respectively. TO-CNFs with nano-scale characteristics improved the air permeability of BAsCNF films, which endowed the sensor with excellent response performance to biogenic amines (BAs). Thus, the BAsCNF produced obvious colour changes from red to yellow-green in response to an increased concentration of BAs, where the limit of detection for BAs was as low as 1 ppm. Meanwhile, the discoloration trend of the BAsCNF in the freshness detection of shrimp and pork was consistent with the variation of the key indicators during storage, such as the content of total volatile basic nitrogen and the total number of colonies. The results suggest that the BAsCNF sensor possessed high detection accuracy and broad application prospects in the field of food safety.