鱿鱼丝加工中真菌菌相变化规律及优势真菌的分离鉴定

Changes of Fungal Flora during Processing of Shredded Squid and Isolation and Identification of the Predominant Fungus from the Product

为减少鱿鱼丝加工过程中真菌污染,提高鱿鱼丝产品的质量,将传统的微生物鉴定技术与5.8S r DNA-ITS序列分析法相结合,并通过系统发育树分析,探索鱿鱼丝加工过程中真菌菌相变化规律及优势菌株。结果表明,在鱿鱼丝加工过程中,不同阶段样品中真菌数量差异显著(p<0.05),在加工终点(即烘干包装后)时真菌数量高达2.61 log cfu/g,其中调味和烘干包装阶段是真菌污染的主要环节。加工终点的鱿鱼丝中分离出6种酵母菌和4种霉菌,经测序并通过National Center for Biotechnology Information(NCBI)数据库比对,确定它们分别属于假丝酵母属(Candida sp.)、隐球酵母属(Cryptococcus sp.)、座囊菌属(Dothideomycetes sp.)、胶红酵母属(Rhodotorula sp.)、丝孢酵母属(Trichosporon sp.)、茎点霉属(Phoma sp.)、青霉属(Penicillium sp.)、曲霉属(Aspergillus sp.)、枝孢霉属(Cladosporium sp.)。其中,青霉菌(M-03)和假丝酵母菌(Y-04)为鱿鱼丝加工过程中的优势菌,在加工终点时的数量分别为1.85 log cfu/g和2.15 log cfu/g。

The purpose of this study was to reduce fungal contamination in the processing of shredded squid and improve product quality. A combination of traditional microbial identification techniques, sequence analysis of 5.8S r DNA-internal transcribed spacer（ITS）, and phylogenetic tree analysis were used to examine changes in fungal flora as well as to identify the dominant fungal strains in shredded squid during production. The results showed that significant differences in fungal counts were seen at different stages of squid processing. The fungal population reached 2.61 log cfu/g at the end of processing（after drying and packaging）, and the flavoring, drying, and packaging stages were the main stages for fungal contamination. Six types of yeast and four types of mold were isolated from shredded squid at the end of processing. After sequencing and comparing with sequences from the National Center for Biotechnology Information（NCBI） database, these fungi were identified as Candida sp., Cryptococcus sp., Dothideomycetes sp., Rhodotorula sp., Trichosporon sp., Phoma sp., Penicillium sp., Aspergillus sp., and Cladosporium sp.. Among them, Penicillium（M-04） and Candida（Y-06） were the predominant fungi found in the processing of shredded squid, and their corresponding counts at the end of the processing were 1.85 log cfu/g and 2.15 log cfu/g, respectively.