摘要
目的探究鼠李糖乳杆菌(Lactobacillus rhamnosus,ATCC7469)不同接种液浓度和培养时间对微孔板法检测乳粉中叶酸含量的影响,优化实验条件。方法测定鼠李糖乳杆菌接种的种子培养液不同培养时间的吸光度值,分析得出其最佳接种时期;在此基础上,在不同浓度接种液和不同培养时间条件下,用ELISACalc软件对标准曲线进行Logistic曲线拟合,用Origin 2022进行图形绘制和数据处理,通过对标准曲线系列生长曲线的绘制和质控样10次独立检测结果的分析,确定了方法中接种液浓度和微孔板接种物的培养时间;对优化后的方法进行方法学指标考察。结果将鼠李糖乳杆菌用MRS琼脂进行活化,种子培养液培养至16 h,接种液透光率稀释在50%~70%,培养40 h,叶酸标准曲线系列各管菌体生长均进入稳定期,无明显吸光度值变化,可以保证试验的可行性和稳定性;在此条件下,对质控样(QC-IP-737)进行10次独立检测的结果分别为111.80μg/100 g和109.87μg/100 g,接近质控样特性值,且标准差均小于5%,具有较好的准确度和精密度。结论通过对接种液浓度和培养时间的探究,在GB 5009.211-2022微孔板法基础上优化了实验条件,为微孔板法检测乳粉中叶酸含量的应用提供参考。
Objective To explore the effects of different inoculum concentration and incubation time of Lactobacillus rhamnosus(ATCC7469)on folic acid content test in milk powder by microporous plate method,and to optimize the experimental conditions.Methods To absorbance values of seed culture medium inoculated with Lactobacillus rhamnosus for different periods of incubation time were determined,and the optimum inoculation period was obtained by analysis.Based on this,under the conditions of different inoculum concentration and different incubation time,ELISACalc software was used to perform Logistic curve fitting on standard curves,and Origin 2022 was used for graphic drawing and data processing.The inoculum concentration and the incubation time of microplate inoculum were determined through drawing the growth curve of the standard curve series and analyzing the results of 10 independent tests of quality control samples.The methodological indicator evaluation was conducted on the optimized method.Results Activating Lactobacillus rhamnosus with MRS agar,incubating the seed culture medium for 16 hours,diluting the transmittance of the inoculum between 50%and 70%and incubating for 40 hours,the growth of Lactobacillus rhamnosus in all tubes of the folic acid standard curve series entered a stable period,and there was no significant change in the absorbance value,which could ensure the feasibility and stability of the test.Under these conditions,the results of 10 independent tests on the quality control samples(QC-IP-737)were 111.80μg/100 g and 109.87μg/100 g,respectively,which were close to the characteristic values of the quality control sample,and the standard deviation was less than 5%with good accuracy and precision.Conclusions By exploring the inoculum concentration and incubation time,the experimental conditions were optimized based on GB 5009.211-2022 microporous plate method,and it provided a reference for the application of microporous plate method for detecting folic acid content in milk powder.
作者
宁鑫思
陈友军
贺巧玲
张建军
陈学强
NING Xinsi;CHEN Youjun;HE Qiaoling;ZHANG Jianjun;CHEN Xueqiang(Sichuan Food Inspection and Research Institute,Chengdu 610097,Sichuan Province,China)
出处
《预防医学情报杂志》
2025年第5期699-706,共8页
Journal of Preventive Medicine Information
基金
四川省科技计划项目(项目编号:2023YFS0398)。
关键词
叶酸
微孔板法
接种液浓度
培养时间
folic acid
microporous plate method
inoculum concentration
incubation time
