The Effect of Dielectric Barrier Discharge Plasma Treatment on The Microorganisms Found in Raw Cow's Milk

Abstract

Milk is an essential source of nutrition especially for the breastfed infants. Sterilization of milk is necessary because it can be contaminated by microorganisms due to unhygienic collection and storage conditions. In this study, the sterilization of raw cow milk was performed by using dielectric barrier discharge (DBD) plasma method. Raw milk was transferred to the plasma reactor and dielectric barrier discharge cold plasma was performed by changing various parameters including voltage, exposure time and frequency. It was found that dielectric barrier discharge cold plasma is very effective at sterilization of raw cow milk particularly at room temperature. The optimum parameters that wee demonstrated to completely kill the bacteria in raw milk were experimentally determined to be a 3 kV application voltage, 3 min exposure time and 500 Hz frequency. Additionally, there was almost no important change in pH value of cow milk after DBD plasma treatment (The average pH was 6.2). Pathogen microorganisms found in milk produces metabolites (during storage and transport) that have adverse effects on health. The method developed by us in this study will be used in a future study to develop a prototype of a sterilization device that can be integrated into the current milking system and can be continuously applied. Thus, the sterilization of milk during milking process could potentially be an extremely effective method for maintaining its quality and nutritional value. Furthermore, since the DBD plasma method is an ultra fast process that operates under ambient temperatures (ideal for thermolabile products) at a low running cost and is environment-friendly, it can be used for the sterilization of a wide range of liquid food products.