Investigating the effect of cold plasma on the disinfection and quality of Iranian white cheese during the storage period

Cheese is one of the most consumed milk products. At present, one of the most widely used salty white cheeses in Iran is the cheese produced by the ultrafiltration method. Non-thermal (cold) plasma is a new method to remove food microorganisms. In this research, the effect of cold plasma on the reduction of microbial load and qualitative and rheological characteristics of cheese samples produced through different tests was investigated. The samples were prepared and produced in Pegah Hamadan Company under two microbial treatments (yeast mold and coliform) and the duration of plasma application at two levels (7 and 13 minutes) and the control sample (lack of contamination, no plasma) and during the storage period of 30 days. They were tested once every ten days with 2 repetitions by colorimetric tests, pH, and tissue test (TPA) and Warner test. The results of the statistical analysis of the obtained data showed a significant difference in the evaluated traits between the control sample and the treatments that underwent the cold plasma process. The value of parameter L* in the samples treated with cold plasma decreased compared to the control sample, also the index b* (yellowness index) did not increase significantly for all cheese samples at the end of the storage period. There was no significant difference in the amount of Springiness between the samples treated with plasma and the control sample, and the amount of gumminess did not increase significantly during the storage period. There was a significant increase in shear modulus, shear stress and shear force between the first day and the 10th, 20th, and 30th days. It can also be concluded that the treatments with coliform contamination have less stiffness and strength than other treatments and the type pollution added to the samples is the cause of this significant difference.