Gelman A, Glatman L, Drabkin V, Harpaz S
Fishery Products Laboratory, Kimron Veterinary Institute, Bet Dagan, Israel.
J Food Prot. 2001 Oct;64(10):1584-91. doi: 10.4315/0362-028x-64.10.1584.
Sensory and microbiological characteristics of pond-raised freshwater silver perch (Bidyanus bidyanus) fish, during cold storage over a period of 25 days were evaluated. Whole fish (averaging 400 g each) were stored in cold storage rooms at either 0 to 2 degrees C, 5 degrees C, or 5 degrees C + potassium sorbate as a preservative. The organoleptic and hypoxanthine test results show that the treatment of potassium sorbate can slow the process of spoilage by about 5 days. Yet, the most important factor affecting the shelf life of these fish is the storage temperature. Keeping the fish at 0 to 2 degrees C can prolong the storage prior to spoilage by 10 days compared with those kept at 5 degrees C. These results obtained through organoleptic tests are corroborated by both the chemical (hypoxanthine and total volatile basic nitrogen) and to some extent by the physical (cosmos) tests. The initial total bacteriological counts were 5 x 10(2) CFU/cm2 for fish surface and <10(2) CFU/g for fish flesh, and these counts rose continuously, reaching about 106 CFU/g (0 to 2 degrees C) and 10(7) CFU/g (5 degrees C) in flesh and 10(7) to 10(8) CFU/cm2 on the surface by the end of the storage period. The addition of potassium sorbate led to a smaller increase in bacterial numbers, especially during the first 15 days. Bacterial composition fluctuated during storage. The initial load on the fish surface was predominantly mesophilic and gram positive and consisted mostly (80%) of Micrococci, Bacillus, and Corynebacterium. During the next 10 days, these bacteria were practically replaced by gram-negative flora comprised mostly of Pseudomonas fluorescens that rapidly increased with storage time and accounted for 95% after 15 days.
对池塘养殖的淡水银鲈（Bidyanus bidyanus）在25天冷藏期间的感官和微生物特性进行了评估。整条鱼（平均每条400克）分别储存在0至2摄氏度、5摄氏度或添加山梨酸钾作为防腐剂的5摄氏度冷藏库中。感官和次黄嘌呤测试结果表明，山梨酸钾处理可使腐败过程延缓约5天。然而，影响这些鱼货架期的最重要因素是储存温度。与储存在5摄氏度的鱼相比，将鱼保存在0至2摄氏度可使变质前的储存期延长10天。通过感官测试获得的这些结果得到了化学（次黄嘌呤和总挥发性碱性氮）测试以及在一定程度上物理（宇宙）测试的证实。鱼表面的初始细菌总数为5×10²CFU/cm²，鱼肉中<10²CFU/g，这些数量持续上升，到储存期结束时，鱼肉中达到约10⁶CFU/g（0至2摄氏度）和10⁷CFU/g（5摄氏度），表面达到10⁷至10⁸CFU/cm²。添加山梨酸钾导致细菌数量增加较少，尤其是在最初的15天内。储存期间细菌组成波动。鱼表面的初始菌群主要是嗜温菌和革兰氏阳性菌，主要（80%）由微球菌、芽孢杆菌和棒状杆菌组成。在接下来的10天里，这些细菌实际上被革兰氏阴性菌群取代，主要由荧光假单胞菌组成，随着储存时间迅速增加，15天后占95%。
