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

一种利用氨肽酶法检测原料奶中嗜冷菌的方法

Abstract

本发明公开了一种利用氨肽酶法检测原料奶中嗜冷菌的方法,该方法预先将原料奶离心处理,除去其中的脂肪层和水层,得到富含嗜冷菌菌体和乳蛋白质的沉淀物层;在无菌三羟甲基氨基甲烷-盐酸缓冲液中将沉淀物层中的嗜冷菌活菌体的氨肽酶与L-丙氨酸-对硝基苯胺直接进行氨肽酶反应,最大限度的保证了嗜冷菌的存活,然后再除掉体系中的乳蛋白,提取清澈的反应液,避免了预先提取嗜冷菌菌体而存在的活菌回收率高低的问题,减小了实验的系统误差,同时可利用待测液吸光值与嗜冷菌数量之间的对应关系,对原料奶中嗜冷菌的数量进行定量检测。
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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Patent Citations (2)

    Publication numberPublication dateAssigneeTitle
    CN-101149355-AMarch 26, 2008东北农业大学Method for detecting cow's milk salmonella
    CN-1715875-AJanuary 04, 2006浙江大学Quick method for detecting whether to blend reduced milk in fresh milk

NO-Patent Citations (2)

    Title
    《International Dairy Journal》 20051231 Susana Manzano et al. A rapid method for the estimation of the microbiological quality of refrigerated raw milk based on the aminopeptidase activity of Gram-negative bacteria 第79-84页 1-5 , 2
    《食品科学》 20091231 吕元等 原料奶嗜冷菌快速检测方法研究进展 第274-280页 1-5 第30卷, 第3期 2

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