冷藏鲳鱼贮藏期间的细菌种群变化

Bacterial Species Changes in Pampus argenteus During Chilled Storage

摘要:

分析了鲳鱼(Pampus argenteus)冷藏期间的感官、pH值、微生物指标及主要细菌种群变化。研究表明,初始样品pH值为7.217±0.015,菌落总数(CFU/g)的对数值为3.967±0.012;初始细菌种类较多,其中45.92%为革兰氏阴性菌,54.08%为革兰氏阳性菌,优势菌为腐生葡萄球菌(Staphylococcus saprophyticus 28.81%)、松鼠葡萄球菌(Staphylococcus sciuri 15.38%)、嗜冷杆菌(Psychrobacter spp.12.09%)、草莓假单胞菌(Pseudomonas fragi 9.02%)、荧光假单胞菌(Pseudomonas fluorescens 8.53%)与腐败希瓦氏菌(Shewanella putrefaciens 6.39%),同时检出一定比例的成团肠杆菌、微杆菌与嗜根库克菌。冷藏过程中,腐生葡萄球菌与松鼠葡萄球菌等生长受到抑制,细菌菌相组成逐渐单一,适应低温环境条件的革兰氏阴性菌比例逐渐增加,在贮藏的第3、5、7天至货架期终点(pH值为8.057±0.005,菌落总数(CFU/g)的对数值为9.137±0.032)时,阴性菌比例分别达到83.82%、95.86%、96.88%与93.57%。其中,假单胞菌与腐败希瓦氏菌增长显著,在贮藏末期比例为45.71%与33.57%,荧光假单胞菌(35.00%)明显多于草莓假单胞菌(10.71%)。

Abstract:

In this paper,quality changes in Pampus argenteus during chilled storage(4+1) ℃ were investigated in the aspects of sensory,pH value and aerobic plate count(APC),and its bacterial flora changes were also qualitatively and quantitatively studied. The results showed that TPC and the mean values of pH of sample at the initial storage were(3.967 ±0.012)lg(CFU/g),(7.217 ±0.015) respectively. 45.92% gram negative bacteria and 54.08% gram positive bacteria were found in it,the dominant bacterial flora were composed of Staphylococcus saprophyticus(28.81%),Staphylococcus sciuri(15.38%),Psychrobacter spp.(12.09%),Pseudomonas fragi(9.02%),Pseudomonas fluorescens(8.53%) and Shewanella putrefaciens(6.39%). A few percent of Enterobacter agglomerans,Microbacterium esteraromaticum and Kocuria rhizophila were also found.The growth of Staphylococcus saprophyticus and Staphylococcus sciuri were inhibited during storage at low temperature,then the composition of bacteria flora gradually became simple,and the percent of gram negative bacteria which were suitable for low temperature increased significantly. The gram negative bacteria were 83.82%,95.86%,96.88% and 93.57% in the period of 3rd,5th,7th,9th day respectively,indicating Pseudomonas spp.(45.71%) and Shewanella putrefaciens(33.57%) were the most predominated spoilage bacteria of Pampus argenteus stored at(4+1) ℃. The species changes of Pseudomonas spp. indicated that the major species were Pseudomonas fluorescens(35.00%) and Pseudomonas fragi(10.71%).