Moderate electric field pasteurization of milk in a continuous flow unit: Effects of process parameters, energy consumption, and shelf-life determination

摘要

This study presents a new non-thermal moderate electric field (MEF) process for milk pasteurization. To evaluate the applicability of this process, fresh milk was treated by MEF at electrical field strength (EFS) of 8.33, 14.58, and 20.80 V/cm and mass flow rates (MFR) of 0.018, 0.042 and 0.077 kg/s to compare the microbiological quality, alkaline phosphatase activity, chemical composition, and some physical properties of the product with those of conventionally pasteurized (15 s at 72 ?C) and raw milk. The changes in the total count of bacteria (TCB) and titratable acidity of samples were observed during 18 days of storage at 5 ?C for shelf-life estimation. The results showed that MEF reduced energy consumption by 63% in comparison with thermal pasteurization. Also, MEF treatment inactivated coliforms (100%), Staphylococcus aureus (100%), psychrophiles (100%), yeasts and molds (100%), and alkaline phosphatase (100%) while keeping the processing temperature below 22 ?C. Also, TCB of sample was reduced by increasing the EFS from 8.33 to 20.8 V/cm and decreasing the MFR from 0.0774 to 0.0185 kg/s. The longest shelf-life of MEF samples, i.e., 15 days, was observed at EFS of 20.80 V/cm and MFR of 0.018 kg/s which was better than that of thermal pasteurization samples, i.e., 9 days.