The Growth Rate of Psychrophilic and Mesophilic Bacteria in Raw Milk Stored at Low and Room Temperature

The growth rate of psychrophilic and mesophilic bacteria in raw milk stored at low and room temperature was studied.The results were as follows:1. The maximum number of psychrophilic bacteria in raw milk stored at 5-7°C reached 108-109per ml after 5-7 days and the time required to reach the maximum count of the bacteria was affected by their initial counts. The similarity of the growth rates was observed for psychrophilic and mesophilic bacteria when stored at 20-25°C.2. Colony forming percentage of the strains isolated from the culture placed at 5-7°C for 7 days was 54% when maintained at 37°C for 2 days.The majority of isolated psychrophilic bacteria were gram-negative, catalase-positive rods.