【摘要】 对0、5和10℃冷藏养殖罗非鱼货架期终点的特定腐败菌进行定性和定量研究,并建立特定腐败菌的生长动力学模型。实验结果表明,0、5和10℃冷藏养殖罗非鱼货架期终点时,假单胞菌占总菌数比例分别为80.7%、68.1%和57.5%。该类菌在营养琼脂和胰酶解大豆胨琼脂培养基上菌落圆状隆起,边缘整齐,透明,无色;菌体为革兰氏阴性杆菌,极生单鞭毛,具有运动性,大小为(0.5～0.7)μm×(1.6～3.2)μm;氧化酶反应为阳性,不能利用海藻糖、棉子醇和甘露醇等;直链、支链、环丙基和羟基脂肪酸等被检出,富含单不饱和脂肪酸(50.18%),主要脂肪酸有16∶1ω7c、iso-15∶0、16∶0和17∶1ω8c,比例分别为26.16%、14.83%、7.96%和3.94%;Riboprinter测试其核糖体型为56-S-7。采用修正的Gompertz方程拟合假单胞菌生长模型表明,0、5和10℃冷藏过程延滞时间分别为(59.63±61.88)、(7.25±24.06)和(3.95±9.83)h;最大比生长速率分别为(0.02±0.00)、(0.04±0.00)和(0.08±0.01)/h。更多还原

【Abstract】 The specific spoilage organisms (SSO) in cultured tilapia at the end of shelf life during storage at 0, 5 and 10 ℃ were qualitatively and quantitatively investigated, and the growth model of SSO was established. The results indicated that the percentage of Pseudomonas spp. in total bacteria in the tilapia were 80.7%,68.1% and 57.5% at the end of shelf life of tilapia stored at 0, 5 and 10 ℃, respectively. Colonies of Pseudomonas spp. on nutrition agar and trypticase soy broth agar were circular apophysis with smooth edge, transparent and colourless; The cells were gram negative rod (0.5~0.7 μm×1.6~3.2 μm) and motile by means of polar flagellum; Positive for oxidation,but the strains could not assimilated trehalose, mannitol and raffinose, etc. A variety of acids were detected in these organisms, including branched and straight-chained acids, cyclopropane, and hydroxy acids. Unsaturated fatty acids comprised a large part of all fatty acids (50.18%), and the major ones were 16∶1ω7c, iso-15∶0, 16∶0 and 17∶1ω8c, which were 26.16%, 14.83%, 7.96% and 3.94% of total fatty acids, respectively. The type of ribosome of these bacteria was 56-S-7, as tested by Riboprinter. The growth dynamic for Pseudomonas spp. was fitted by modified Gompertz equation. The results showed that lag time reached(59.63±61.88), (7.25±24.06) and (3.95±9.83)h during storage at 0, 5 and 10 ℃, respectively. The maximum specific growth rates for Pseudomonas spp. were (0.02±0.00)h-1, (0.04±0.00)h-1 and (0.08±0.01)h-1 at 0, 5 and 10 ℃, respectively.更多还原