真空包装牛肉冰温贮藏过程中优势腐败菌的分离鉴定

Isolation and identification of the dominant spoilage organisms in the vacuum packed beef

为确定导致真空包装牛肉腐败的优势致腐菌,将牛肉真空包装后在冰温(-1±1)℃条件下贮藏,利用选择性培养基(CFC培养基、STAA培养基、MRS培养基、VRBDA培养基)分离筛选各类腐败菌,并通过分离纯化、形态学鉴定、16S r DNA序列分析等手段,对冰温贮藏真空包装牛肉的优势腐败菌进行鉴定。结果表明:真空包装牛肉在冰温条件下贮藏至15 d时优势腐败菌为乳酸菌(8.54 lg cfu/g)、假单胞菌(8.28 lg cfu/g),热死环丝菌和肠杆菌也是腐败菌,数量分别为6.51 lg cfu/g和5.31 lg cfu/g。形态和分子学鉴定证实,真空包装牛肉的优势腐败菌株包括变形斑沙雷菌(Serratia proteamaculans)、水生拉恩氏菌(Rahnella aquatilis)、热死环丝菌(Brochothrix thermosphacta)、干酪乳杆菌(Lactobacillus sakei)、分叉肉毒杆菌(Carnobacterium divergens)和脆假单胞菌(Pseudomonas fragi),以及未能鉴定到种的沙雷氏菌属、肉食杆菌属的菌株。

To learn about the micro organisms which cause the corruption of vacuum-packed beef,we put the vacuum-packed beef stored under the ice temperature condition（-1±1）℃.Isolation and screening of all kinds of dominant spoilage bacteria,through selective medium（CFC medium,STAA medium,MRS medium,VRBDA medium）.By isolation and culture,morphological identification,16 S r DNA sequencing analysis,the dominant bacteria species of ice-temperature storage beef under vacuum condition were identified.The results showed that the vacuum-packed beef could be kept fresh for 15 d under the ice temperature condition（-1±1）℃.Lactobacillus sp.（8.54 lg cfu/g）and Pseudomonas sp.（8.28 lg cfu/g）were dominant spoilage bacteria.Brochothrix thermosphacta（6.51 lg cfu/g）and Enterobacter sp.（5.31 lg cfu/g）also were spoilage bacteria.Confirmed by morphology and molecular identification,the dominant spoilage bacteria which cause the corruption of vacuum-packed beef including Serratia proteamaculans,Rahnella aquatilis,Brochothrix thermosphacta,Lactobacillus sakei,Carnobacterium divergens,Pseudomonas fragi and Serratia sp.and Carnobacterium sp.are not identification to species.The research results provided a theoretical basis for the control of the vacuum packaged beef by the antibacterial measures.