牛肉预煮液作为培养基氮源的可能性探讨

Study on the possibility of pre-cooked beef fluid nitrogen as a medium to explore

牛肉预煮液进行离心、过滤等预处理后,将其浓缩至原体积的75%、50%,主要测定总氮、氨基酸态氮含量。以金黄色葡萄球菌、大肠杆菌、沙门氏菌为质控菌株,检验三种不同浓度牛肉预煮液替代普通肉汤的灵敏度,并观察三种质控菌株分别在不同浓度牛肉预煮液配制的营养琼脂上生长的菌落形态。结果表明:原液、浓缩至原体积75%、50%浓缩液总氮含量分别为2.044、3.066、4.088mg/mL,氨基酸态氮含量分别为0.945、1.425、1.890mg/mL;磷酸盐实验、碱性沉淀实验、色素生成实验以及灵敏度均符合培养基要求。三种质控菌株的菌落形态、菌落大小、色素生成均符合菌株的生长特性,在50%的浓缩液牛肉预煮液配制的营养肉汤中培养24h,灵敏度均能达到10-9,敏感性最强,故可将总氮、氨基酸态氮含量分别达4.088、1.890mg/mL的浓缩液替代用于此三种质控菌株培养的牛肉浸液。

Pre-cooked beef liquid to centrifugation and filtration etc,was concentrated to the original volume of its 75% ,50%, mainly determination of total nitrogen, amino nitrogen content.Staphylococcus aureus, E. coli, Salmonella strains for quality control,testing of three different concentrations of pre-cooked beef broth liquid alternative to ordinary sensitivity,and to observe the three kinds of quality control strains were pre-cooked beef at different concentrations of nutrient agar solution prepared on the growth of colony morphology.The results showed that：the original pre-cooked beef liquid, concentrated to the original volume of 75 % ,50% concentrated liquid TN contents were 2.044, 3.066,4.088mg/mL, amino acid nitrogen contents were 0.945, 1.425, 1.890mg/mh Phosphate test, alkaline precipitation test, pigment-producing testing and sensitivity met the media requirements.Three kinds of quality control strains of colony morphology, colony size, pigment- producing strains were in line with the growth characteristics.Concentrated solution in 50% of the pre-cooked beef liquid nutrient broth prepared to cultivate 24h sensitivity can reach 10 ＂,the sensitivity of the strongest.Therefore TN, amino nitrogen content were up to 4.088, 1.890mg/mL can be alternative to the concentrated solution of three quality control strains used for this culture of beef extract.