典型冷链贮藏南美白对虾优势菌菌相变化与感官品质相关性分析

Changes in Dominant Bacteria of Penaeus vannameias during Storage Time under Typical Cold Chain Temperature and Its Correlation with Sensory Quality

将南美白对虾在典型冷链温度-23,0,5℃条件下贮藏,通过菌落计数与观察、革兰氏染色、生理生化试验对优势菌进行鉴定,结合感官评分和细菌总数变化规律,分析南美白对虾在典型冷链贮藏温度下优势菌菌相变化与感官品质的相关性。结果表明:典型冷链贮藏温度5℃条件下,南美白对虾细菌总数在第3天时超过6.2 lg(CFU/g),0℃条件下细菌总数在第5天超过6.0 lg(CFU/g),-23℃条件下的细菌总数一直低于4.0 lg(CFU/g)。分离纯化的4种优势菌被鉴定为黄杆菌属、假单胞菌属、不动杆菌属和葡萄球菌属,其中黄杆菌属与假单胞菌属占70%以上,是延长南美白对虾货架期的关键控制菌。结合菌相变化的感官评价表明,0℃和5℃条件下南美白对虾分别经3 d和5 d的贮藏,感官价值大大降低;而-23℃条件下贮藏30 d,其感官品质无明显下降。

Screening and identification of dominant bacteria of Penaeus vannameias stored at typical cold chain temperature of-23, 0, and 5 ℃ were performed by colony forming units, Gram staining and physiological and biochemical screening. Changes in dominant bacteria phase and its correlation with sensory quality were investigated with the evaluation of sensory score and total colony counting. The results showed that the colony forming units reached 6.2 lg（CFU/g）at the third day of storage under 5 ℃, while the same level can be found at the fifth day of storage under 0 ℃. Unlike the temperature of 0 and 5 ℃, the colony forming units was below 4.0 lg（CFU/g） within the whole storage time at-23℃. The screened dominant bacteria were Flavobacterium spp, Pseudomonas spp, Staphylococcus spp, and Acinetobacter spp, of which the bacteria of Flavobacterium spp and Pseudomonas spp were over 70% in volume and were thus the key controlling bacteria for prolonging the shelf life. With bacteria phases change analyzing, sensory quality evaluation indicated that the Penaeus vannameias stored at 0 and 5 ℃ for 3 and 5 days respectively, undergo a significant decrease in sensory value. On the contrary, the sensory quality of Penaeus vannameias maintained well when stored at-23 ℃ for 30 days.