Effect of ozonation and pasteurization on total microorganism, pH and density whole milk and skim milk during cold storage

Abstract Aim of this research was evaluate the differences in physicochemical characteristics and stability during cold storage of whole and skim milk from ozonation as compared to pasteurization. In this current research, descriptive methods was employed consist of two control samples (untreated skim and whole milk) and four treatments: (1) pasteurized skim milk, (2) ozonated skim milk, (3) pasteurized whole milk and (4) ozonated whole milk. Ozonation was carried out for 650 seconds at 0.36 L/min for whole milk and 5.01 L/min for skim milk, meanwhile, pasteurization process was performed at 72 °C for 15 seconds. The reduction of microorganisms after treatment of pasteurized skim milk, ozonated skim milk, pasteurized whole milk and ozonated whole milk, respectively were 2.97, 2.16, 3.09 and 1.7 log cycle. During storage, ozonated samples, had increased density faster than pasteurized samples, ozonated skim milk also has largest increase in growth microorganisms, meanwhile, ozonated whole milk has the fastest decreased of pH than other samples. Therefore, ozonation treatment can be used as milk pre-treatment to reduce microorganisms, however, this treatment must be carried out with other preservation process.