Abstract: Along with life improvement, dairy products quality is enhanced day after day. In the dairy products, microorganism's pollution becomes the key factor that affects the market competition. When milk is stored, the mass of Psychrophile can generate protease and lipase which can withstand pasteurization, let alone Ultra-high temperature (UHT) instantaneous sterilization. They decompose protein and fat. These decomposition products will cause the dairy products change relish, drop quality, shorten guarantee period, thus having serious impact on product quality and harming consumer's health finally. To reduce the harm caused by Psychrophile, examining and controlling the raw milk in early stage is the point.
The article encircles Psychrophile in the cow's milk to launch. We used the cow meat extract and protein peptone culture medium and CVT specific culture medium to isolate Psychrophile from the cow's milk, and appraised bacterium strain by morphological character observation, Gram’s staining and common bacterium physiology biochemistry experiment(H2O2 experiment, M.R experiment, V-P determination, etc.), then inferred bacteria genus. The results indicate that they are bacillus and coccus. According to the bacteria gene sequence, we also designed PCR primer, and collected genome DNA for PCR rapid test, then tested and contrasted sequence. We chose 9 strains of Psychrophile that were isolated from milk for testing and contrasting sequence. There have 6 strains of Psychrobacter.
Keywords: Milk; Psychrophile; PCR Test
