杯碟法中藤黄微球菌的添加方式对生鲜乳中β-内酰胺酶检出限的影响  

Effect of Two Addition Methods of Micrococcus Luteus In Cylinder Plate Methd on the Determination of β-lactamase in Fresh Milk

作　　者：刘旸 张丽宏 房玉国 王胜男 王淼 黄艳玲 LIU Yang;ZHANG Lihong;FANG Yuguo;WANG Shengnan;WANG Miao;HUANG Yanling(Heilongiang Green Food Science R esearch Institute,Harbin 150028,China;Heilongjiang Institute of Standard,Harbin 150028,China)

机构地区：[1]黑龙江省绿色食品科学研究院,哈尔滨150028 [2]黑龙江省标准化研究院,哈尔滨150028

出　　处：《中国乳品工业》2021年第2期39-41,55,共4页China Dairy Industry

摘　　要：由于β-内酰胺酶是不允许添加在生鲜乳中的能分解β-内酰胺类抗生素的"解抗剂"。β-内酰胺酶分解β-内酰胺类抗生素产生的络合物,能引起人体的过敏反应,对婴幼儿的健康损害很大。所以在生鲜乳检验中,提高β-内酰胺酶的检出限就变得尤为重要。尤其在杯碟法中,β-内酰胺酶的检出限越低,抑菌圈的轮廓越接近圆形、边缘越清晰可见、测量就越准确。在菌悬液终浓度都为1×108CFU/mL、每个平皿中都加入15 mL培养基的条件下,研究两种添加藤黄微球菌的方法的检出限。方法一:15 mL含有藤黄微球菌菌悬液的培养基制成的单层培养基。方法二:在10 mL空白培养基上覆盖一层5 mL含藤黄微球菌菌悬液的培养基,制成的双层培养基。采用杯碟法测定模拟样品中的β-内酰胺酶检出限,方法一β-内酰胺酶的检出限在0.0002~0.00025 U/mL之间,方法二β-内酰胺酶的检出限在0.00005~0.0001 U/mL之间,可见方法二的灵敏度明显比方法一的灵敏度要高。Sinceβ-lactamase is not allowed to be added in fresh milk to break downβ-lactam antibiotics"antidote".β-lactamase decomposesβ-complex produced by lactam antibiotics,which can cause allergic reactions in human body and greatly damage the health of infants and young children.So it is very important to improve the detection limit ofβ-lactamase in fresh milk test.Especially in the cup-dish method,the lower the detection limit ofβ-lactamase,the closer the contour of the bacteriostasis circle is to the circle,the clearer the edge is visible,and the more accurate the measurement is.Under the condition that the final concentration of bacterial suspension was 1×108 CFU/mL and 15 mL medium was added to each plate,the following two methods of adding Micrococcus luteus were studied.Method 1:the monolayer medium containing 15 mL suspension was made directly.Method 2:A double-layer medium containing 5 mL of Micrococcus luteus suspension was covered on 10 mL blank medium.Determination ofβ-lactamase in simulated samples by Cylinder Plate method,the detection limit of method 1 is between 0.0002~0.00025 U/mL and that of method 2 is between 0.00005~0.0001 U/mL.It can be seen that the sensitivity of method 2 is obviously higher than that of method 1.

关 键 词：藤黄微球菌 Β-内酰胺酶 杯碟法 双层培养基 检出限 

分 类 号：TS252.7[轻工技术与工程—农产品加工及贮藏工程]