The Study On Isolation,Identification And Biological Characteristics Of Psychrophlic Bacteria In Raw Milk

The Psychrophilic bacteria is one of the reasons that cause a variety of harmful effects of low temperature preserve food products. In order to research the method to solve the problems, the paper studied the Psychrophilic bacteria in the raw milk Preserved in low temperature. By taking use of plate counting method, the effects of mediums was studied, and the results showed that the medium Lais is the optimum medium. It could screen most of the Psychrophilic bacteria, as far as species and quantities is concerned, and the separation results could reflect the basic status of the Psychrophilic bacteria in raw milk.27 strains of Psychrophilic bacteria were screened out by observing bacterial form properties of colony and gram reaction and so on. Through the studies of morphological, physiological and biochemical characteristics, the 27 strains were idendified. Among the 27 strains,7 strains were vested in Aeromonas,3 strains were vested in Pasteurella,3 strains were vested in Flavobacterium,1 strain was vested in Proteus, 4 strains was vested in Arthrobacter, 1 strain was vested in Brevibacterium,1 strain was vested in Micrococcus,1 strain was vested in Pediococcus, 1 strain was vested in Lactococcus,1 strain was vested in Trichococcus. But 3 strains are still need to observe, they have many differences in character of the paper . The paper studied biological characteristics of 27 strains. by the liquid culturing, the optimum growth temperature, pH values, the aerobium, and property of growth were obtained for each of the 27 strains. The study will provide a the oretical base for hazard analysis, and establishment of processing technologies, preserving conditions.