摘要
目的研制黑曲霉菌标准物质,并将其用于食品检测。方法通过显微形态及转录间隔区(internal transcribedspacer,ITS)位点测序,对研究用菌株进行菌种鉴定确认后冻干,制备10^(4)CFU/样品浓度的标准物质。通过对标准物质样品均匀性、运输稳定性、储藏稳定性以及在不同食品基质中使用效果的检验,结合3家实验室的协作定值实验对黑曲霉菌标准物质样品进行评价。结果CMCC98003经肉眼观察菌落绒状,黑色孢子头,菌落反面呈无色或淡黄色有皱褶。制片后显微镜下观察,可见顶囊呈球形,小梗,大梗,分生孢子粗糙,分生孢子梗宽且光滑,孢梗颈,符合黑曲菌形态特性;ITS位点测序结果与美国国家生物信息中心基因库中已有序列比对,匹配最优结果为黑曲霉菌。通过SPSS软件单因素方差分析结果为F0.05(19,20)=2.137,F=1.614<F0.05,符合均匀性要求。黑曲霉菌标准物质在4℃放置28 d,-20℃放置90 d,25、37℃放置7 d进行检测,菌浓度均维持在10^(4)CFU/样品;不同食品基质中的适用性检验可见所有样品均能回收;3家单位协作标定结果均为10^(4)CFU/样品。结论本研究制备的黑曲霉菌标准物质可以满足日常霉菌计数检验需求,可用于实验室间及实验室内结果比对,以期提高实验室检验人员的检验水平。
Objective To develop a standard substance with homogeneity and stability meeting the requirements of standard materials,and apply it to the quality control and laboratory examination of daily detection of Aspergillus niger in the laboratory.Methods The strains used in the study were identified by micromorphology and sequencing of internal transcribed spacer(ITS)sites,and then lyophilized to prepare 10^(4) CFU/sample concentration standard material.Through the inspection of the uniformity,transportation stability,storage stability and the use effect in different food substrates of the reference material samples,combined with the cooperative fixed value experiment of 3 laboratories,the Aspergillus niger reference material samples were evaluated.Results The colony of CMCC98003 was fluffy and black spore head,the reverse side of the colony was colorless or light yellow with wrinkles.Under the microscope after production,it could be seen that the vesicle was spherical,small stem and large stem,the conidia was rough,the conidia stem was wide and smooth,and the spore stem neck conformed to the morphological characteristics of Aspergillus niger;the sequencing results of its loci were compared with the existing sequence alignment in the gene bank of the national biological information center of the United States,and the best matching result was Aspergillus niger.The results of one-way variance analysis by SPSS software were F0.05(19,20)=2.137,F=1.614<F0.05,which met the uniformity requirements.The concentration of Aspergillus niger standard substance was maintained at 104 CFU/sample when it was placed at 4℃ for 28 d and-20℃ for 90 d;the transport stability was tested at 25 and 37℃ for 7 d,and the bacterial concentration was maintained at 10^(4)CFU/sample;the applicability test in different food matrices showed that all samples could recover this standard sample;the collaborative calibration results of the 3 laboratories were 10^(4)CFU/sample.Conclusion The standard materials of Aspergillus niger prepared in this study can meet the needs of daily mold count test,which can be used for the comparison of results between laboratories and within laboratories in order to improve the test level of laboratory inspectors.
作者
白继超
任秀
陈怡文
余文
赵琳娜
路勇
崔生辉
BAI Ji-Chao;REN Xiu;CHEN Yi-Wen;YU Wen;ZHAO Lin-Na;LU Yong;CUI Sheng-Hui(National Institutes for Food and Drug Control,Beijing 100050,China)
出处
《食品安全质量检测学报》
CAS
北大核心
2021年第22期8758-8764,共7页
Journal of Food Safety and Quality
基金
国家重点研发计划项目(2018YFC1603900)。
关键词
黑曲霉菌
标准物质
转录间隔区位点
Aspergillus niger
standard materials
internal transcribed spacer sites
