Predicting chemical shelf life of mozzarella cheese submitted to irregular refrigeration practices by Nuclear Magnetic Resonance spectroscopy and statistical analysis

Abstract The complex mixture found in mozzarella cheese favors microorganism proliferation that causes spoilage. Appropriate refrigeration during storage is one step in the supply chain that is critical to guarantee food quality. However, the impact of the absence of night-time refrigeration, practiced by some commercial establishments, in mozzarella chemical profile has not yet been investigated. To this end, during the evening the simulation of improper refrigeration was carried out using an uncovered Styrofoam box containing ice, allowing the system to reach the thermal balance with the environment. The key degradation compounds produced in mozzarella cheese from simulated inadequate refrigeration were identified and quantified using NMR (Nuclear Magnetic Resonance). While the composition and physicochemical analyses were unable to distinguish refrigeration practices, the NMR data revealed that the succinate contents changed significantly between different refrigeration treatments. At the labelled expiry date, inadequate refrigeration had led to an increase in the succinate content of more than 600%. The results suggested a reduction of 4 weeks of the chemical shelf life. Together, NMR and Principal Response Curve analysis are powerful tools to identify mozzarella cheese submitted to different refrigeration conditions.