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°) 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° readings from individual batch-calibrated sensors were converted into the O(2) concentration by applying the following calibration equation: O(2) (%) = 0.034 * dphi°(2) − 3.413 * dphi° + 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° to 56.02°. The DIY sensor system demonstrated ease of use on-site, fast measurement time, high sample throughput, low cost and flexibility.