A Simple Sensor System for Onsite Monitoring of O-2 in Vacuum-Packed Meats during the Shelf Life

Vacuum packaging (VP) is used to reduce exposure of retail meat samples to ambient oxygen (O-2) and preserve their quality. A simple sensor system produced from commercial components is described, which allows for non-destructive monitoring of the O-2 concentration in VP raw meat samples. Disposable O-2 sensor inserts were produced by spotting small aliquots of the cocktail of the Pt-benzoporphyrin dye and polystyrene in ethyl acetate onto pieces of a PVDF membrane and allowing them to air-dry. These sensor dots were placed on top of the beef cuts and vacuum-packed. A handheld reader, FirestinGO2, was used to read nondestructively the sensor phase shift signals (dphi degrees) and relate them to the O-2 levels in packs (kPa or %). The system was validated under industrial settings at a meat processing plant to monitor O-2 in VP meat over nine weeks of shelf life storage. The dphi degrees readings from individual batch-calibrated sensors were converted into the O-2 concentration by applying the following calibration equation: O-2 (%) = 0.034 * dphi degrees(2) - 3.413 * dphi degrees + 85.02. In the VP meat samples, the O-2 levels were seen to range between 0.12% and 0.27%, with the sensor dphi signals ranging from 44.03 degrees to 56.02 degrees. The DIY sensor system demonstrated ease of use on-site, fast measurement time, high sample throughput, low cost and flexibility.