湛江地区养殖南美白对虾冷藏期间的菌相分析及优势腐败菌的初步鉴定

将湛江地区养殖的南美白对虾在(4±1)℃条件下进行冷藏保鲜,通过细菌形态观察和生理生化实验对冷藏不同时期的细菌组成进行了定性和定量研究,并对优势腐败菌进行了初步鉴定。结果表明:湛江地区养殖的南美白对虾冷藏初期的细菌总数为2.8×104CFU/g,由10个属的细菌组成,其中有6个属为G-,且它们的数量占细菌总数的80%,其中以黄杆菌和气单胞菌的数量最多,分别占细菌总数的33.3%和13.3%;冷藏的第2天为高品质期,细菌总数为5.1×104CFU/g,黄杆菌(30%)和不动杆菌(16.7%)的数量最多,G-的数量增长到86.7%;随着冷藏时间的延长,细菌种类逐渐减少,货架期终点时细菌总数为3.0×106CFU/g,但只分离到8个属的细菌,其中G-占93.4%,气单胞菌和假单胞菌的数量均增加到16.7%,而黄杆菌减少为26.7%,其他种类的G-均有不同程度的增长。冷藏至第6天,细菌总数高达2.4×107CFU/g,虾肉完全腐败变质,从中分离获得的4个属的优势腐败菌均为G-,它们分别是黄杆菌、希瓦氏菌、假单胞菌和气单胞菌,各自所占比例为28.74%、26.44%、21.84%和16.09%。

The analysis of bacterial flora and preliminary identification of dominant spoilage organisms from Zhanjiang cultured Penaeus vannammei during refrigeration

The Zhanjiang cultured Penaeus vannammei were preserved at(4±1)℃ and its bacterial composition were studied qualitatively and quantitatively through the bacterial morphology and physiological-biochemical experiment at different stages during refrigeration.Furthermore,the dominant spoilage organisms were identified preliminarily.The results indicated that the total number of bacteria was 2.8×104 CFU/g at the initial storage,including 10 genera of bacteria with 6 Gram-negative bacteria which taking up 80% of the total number of bacteria.Among them,the bacteria with highest number were Flavobacterium spp.and Aeromonas spp.,accounting for 33.3% and 13.3% respectively.After refrigerated for 2 days,the total number of bacteria was 5.1×104 CFU/g,Flavobacterium spp.(30%) and Acinetobacter spp.(16.7%) were in the ascendant and the amount of G-grew to 86.7%.As time going on,the types of bacteria gradually reduced and the total bacterial count was 3.0 × 106 CFU/g at the end of shelf life,but only 8 genera of bacteria were separated,of which the amount of G-was 93.4% and the content of Aeromonas spp.and Pseudomonas spp.both increased to 16.7% while that of Flavobacterium spp.reduced to 26.7%.The other types of G-were grown in varying degrees.On the 6th days,the total number of bacteria was up to 2.4×107 CFU/g and the Penaeus vannammei completely spoilaged.4 dominant spoilage organisms isolated from the musle of prawn were all G-,which comprised Flavobacterium spp.,Shewanella spp.,Pseudomonas spp.and Aeromonas spp.,with the proportion of 28.74%,26.44%,21.84%,and 16.09%,respectively.