Method for detecting psychrophilic bacteria in crude milk by utilizing aminopeptidase method



The invention discloses a method for detecting psychrophilic bacteria in crude milk by utilizing an aminopeptidase method. In the method, centrifugation is performed in advance on the crude milk to remove a fatty layer and an aqueous layer from the crude milk to obtain a precipitate layer rich in the psychrophilic bacteria and lactoproteins; aminopeptidase reaction is directly performed on the aminopeptidase of living psychrophilic bacteria in the precipitate layer and L-alanine-paranitroaniline in sterile tris-hydroxymethyl aminomethane-hydrochloric acid buffer solution so as to maximally ensure the survival of the psychrophilic bacteria; the lactoproteins are removed from the system and clear reaction solution is extracted so as to solve the problem on a living bacterium recovery rate caused by the in-advance extraction of the psychrophilic bacteria and reduce system errors in experiments; and simultaneously, quantitative detection can be performed on the count of the psychrophilic bacteria in the crude milk by utilizing a corresponding relationship between an absorbance value of liquid to be detected and the count of the psychrophilic bacteria.




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