Studies of spray drying process of sour milk products with the application of ultrasonic vibrations

The article considers the approach to the realization low-temperature spray drying of sour milk products, which is based on the application of ultrasonic action for atomization of raw material and also at the interaction of drops generated by the atomization with the flow of drying agent (air). It is shown, that ultrasonic action both at the stage of spraying and at the stage of interaction of drops with the flow of drying agent does not provide the survival of microorganisms. Ultrasonic atomization of the raw material into the drying chamber leads to the reduction of bacterial count in more than 10 times due the cavitation. The influence by ultrasonic vibrations at moisture evaporation from the drop surface decreases bacterial count in up to 180 times. According to obtained results ultrasonic action does not suit to spray drying of sour milk products, but it can be recommended for drying of thermolabile plant extracts and medicines in order to remove contaminating microorganisms.