加州鲈优势腐败菌的分离鉴定

Isolation and Identification of the Dominant Spoilage Bacteria from California Bass (Micropterus salmoides)

摘要:

为了研究加州鲈的优势腐败菌，采用16S r DNA基因测序手段进行腐败菌的分离鉴定。以感官评价、pH、总挥发性盐基氮（Total volatile base nitrogen，TVBN值）及产量因子（YTVBN/cfu）为指标，对菌种的致腐能力进行系统评估。鉴定结果表明，加州鲈肉样中共分离9种菌，分属普罗维登斯菌属（Providencia），哈夫尼菌属（Hafnia），气单胞菌属（Aeromonas），不动杆菌属（Acinetobacter），肠球菌属（Enterococcus），葡萄球菌属（Staphylococcus），希瓦氏菌属（Shewanella），和巨球菌属（Megasphaera）。其中，革兰氏阳性菌3种，革兰氏阴性菌6种。致腐能力实验结果显示，巴氏葡萄球菌（Staphylococcus pasteuri）样品从高品质终点到达感官拒绝点仅需1.5 h；培养24 h，样品pH最高可达7.35±0.33，TVBN最大可达160.02±0.28 mg/100 g，产量因子YTVBN/cfu可达227.32±1.08（10-9 mg TVBN/cfu），显著高于其他菌种样品（p<0.05）。综上所述，巴氏葡萄球菌具有极强的致腐能力和蛋白质分解能力，是加州鲈鱼肉的优势腐败菌。

Abstract:

In order to study the dominant spoilage bacteria of Micropterus salmoides, the 16S rDNA gene sequencing technique was used to isolate and identify the spoilage bacteria. The sensory properties, pH, total volatile base nitrogen (TVBN) value and yield factor (YTVBN/cfu) were used as indicators for systematic evaluation of the spoilage ability of the bacterium strains. The results showed that 9 strains were isolated from the sample of Micropterus salmoides, including Providencia, Hafnia, Aeromonas, Acinetobacter, Enterococcus, Staphylococcus, Shewanella, and Megasphaera. Among them, three were Gram-positive whilst six were Gram-negative. The results of spoilage ability evaluation revealed that it only took 1.5 h for the sample containing Staphylococcus pasteuri from the high quality level to where sensory rejection occurred. After a 24-h culture, the pH value and TVBN value of the sample containing Staphylococcus pasteuri samples could reach the highest (7.35±0.33 and 160.02±0.28 mg/100 g), with a yield factor YTVBN/cfu of 227.32±1.08 (10-9 mg TVBN/cfu) (which was significantly (p<0.05) higher than those for the samples containing other strains. In summary, Staphylococcus pasteuri has strong spoilage and protein decomposition abilities and is the dominant spoilage bacteria of Micropterus salmoides meat.