Effect of Cold PlasmaTreatment on Physicochemical and Microbiological Properties of Clotted Cream

The aim of this study was to determine the effect of cold plasma treatment, which was applied by using two different gases (O2 and Ar) and their mixtures onto sample surfaces for different intervals, on the physicochemical and microbial parameters of clotted cream during storage for up to 10 days. Cold plasma treatment caused a decrease in pH, aw, L*, and b* values of clotted cream samples and an increase in their a* and TBA values. The pH values of samples ranged from 4.68 to 6.67, and the range for aw values was between 0.903 and 0.803. For TBA, the highest change was observed in the K2 sample with 0.479 mg malondialdehyde/kg. The color L* values of all samples were between 99.79 and 93.82, a* values between 1.82 and 1.22, and b* values between 6.22 and 4.74. Among the treatments, the treatment of O2-Ar gas mixture (50-50%) resulted in the highest decrease in the total counts of aerobic mesophilic bacteria (TMAB), total aerobic psychrophilic bacteria, proteolytic bacteria, yeast-molds, coliform group bacteria, and Staphylococcus aureus. Compared to the control sample, at the end of 10 days of storage, a decrease of 2.41 for TMAB, 3.64 for total yeast-mold, 4.23 for coliform group bacteria, and 4.72 log cfu/g for S. aureus was achieved. Results indicated that the cold plasma treatment did not cause significant changes in the physicochemical values of clotted cream samples but reduced their microbial load.