The authors of this study (here - open access) describe a novel composite thin film based on rhodamine B encapsulated into MOF-5 (Metal Organic Frameworks) as a fluorescence sensor for the real-time verification of the freshness of chilled pork. The composite film can adsorb and respond to the volatile amines produced during the deterioration of pork. The fluorescence intensity of RhB decreased with decreasing freshness. A quantitative model was built using 30 reference samples to predict the freshness indicator (total volatile base nitrogen) as defined by Chinese national standard GB 5009.228-2016. The biosensor compared favourably to the official Kjeldahl method. A qualitative model established by the partial least squares discriminant analysis (PLS-DA) algorithm was able to accurately classify pork samples as fresh, acceptable or spoiled. The article is part of a special issue (here – open access) of Biosensors on rapid non-destructive biosensors for food analysis.