纸盒饮品外包装底部霉菌的分离与鉴定

Isolation and identification of moulds at the bottom of carton beverage packaging

目的鉴别某纸盒饮品外包装底部所长霉菌的类别。方法从外包装底部生长的霉菌菌落中挑菌体,接种于马铃薯葡萄糖琼脂与平板计数琼脂,进行分离纯化培养,确定该霉菌是否为单一菌株;采用水浸片法观察菌落形态与结构特征,进行碳源、氮源实验探究菌株生长特性,提取菌株基因组DNA进行转录间隔区(internal transcript spacer,ITS)鉴定及构建进化树分析对菌株进行分子生物学鉴定。结果该霉菌为尖孢镰刀菌(Fusarium oxysporum),可利用葡萄糖、蔗糖、乳糖等7类碳源及尿素、硝酸钾、硫酸铵等5类氮源,在无氮培养基仍可生长。结论尖孢镰刀菌繁殖速度快、生存能力极强,可产生紫红色物质,对食品外包装感官影响较严重。

Objective To identify the type of mold growing on the bottom of the outer packaging of a carton.Methods The bacteria were isolated and purified from the fungus colonies growing at the bottom of the outer package and inoculated with potato glucose AGAR and plate count AGAR to determine whether the fungus was a single strain.The morphological and structural characteristics of colonies were observed by water immersion tablets,and the growth characteristics of strains were explored by carbon and nitrogen source experiments.The genomic DNA of the strain was extracted for internal transcript spacer（ITS） identification,and an evolutionary tree analysis was constructed to identify the strains in molecular biology.Results The fungus was Fusarium acuminate,which could utilize 7 types of carbon sources such as glucose,sucrose,and lactose,and 5 types of nitrogen sources such as urea,potassium nitrate,and ammonium sulfate,and could still grow in a nitrogen-free medium.Conclusion Fusarium oxysporum has a rapid propagation rate and a strong ability to survive,which can produce purple-red substances and has a more serious sensory impact on food packaging.