Harpaz S, Glatman L, Drabkin V, Gelman A
Department of Aquaculture, Agricultural Research Organization, The Volcani Center, P.O. Box 6, Bet Dagan 50250, Israel.
J Food Prot. 2003 Mar;66(3):410-7. doi: 10.4315/0362-028x-66.3.410.
Sensory and microbiological characteristics of Asian sea bass (Lates calcarifer) fish raised in a freshwater pond were evaluated during cold storage for 33 days. Whole fish (averaging 400 g each) were stored in a cold storage room at 0 to 2 degrees C. Essential oils of herbs--thyme (Thymus vulgaris) and oregano (Origanum vulgare)--added at 0.05% (vol/vol) were used as preservatives. On the basis of the sensory test results as well as the bacteriological tests, the addition of oregano and thyme essential oils can considerably slow the process of spoilage. The fish treated with these oils were still fit for human consumption after 33 days of storage. The results obtained through sensory tests are corroborated to a great extent by the chemical (hypoxanthine) tests and to a lesser extent by the physical (Cosmos units) tests. The initial total bacteriological counts were 1.7 x 10(3) CFU/cm2 on the fish surface and <10(2) CFU/g in the fish flesh, and in the control treatment (without preservatives), these counts rose continuously, reaching around 10(7) CFU/cm2 on the fish surface and 10(3) CFU/g in the flesh after 33 days of storage at 0 to 2 degrees C. The use of herbal essential oils as preservatives, on the other hand, resulted in a maximal count of 10(5) CFU/cm2 on the fish surface, while the bacterial count in the flesh remained <10(2) CFU/g by the end of the 33-day storage period at 0 to 2 degrees C.
对在淡水池塘中养殖的尖吻鲈（Lates calcarifer）在冷藏33天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）储存在0至2摄氏度的冷藏室中。添加0.05%（体积/体积）的百里香（Thymus vulgaris）和牛至（Origanum vulgare）草本植物精油作为防腐剂。根据感官测试结果以及细菌学测试，添加牛至和百里香精油可以显著减缓腐败过程。用这些油处理过的鱼在储存33天后仍适合人类食用。感官测试获得的结果在很大程度上得到了化学（次黄嘌呤）测试的证实，在较小程度上得到了物理（宇宙单位）测试的证实。鱼表面的初始总细菌计数为1.7×10³CFU/cm²，鱼肉中<10²CFU/g，在对照处理（不添加防腐剂）中，这些计数持续上升，在0至2摄氏度储存33天后，鱼表面达到约10⁷CFU/cm²，鱼肉中达到10³CFU/g。另一方面，使用草本植物精油作为防腐剂，鱼表面的最大计数为10⁵CFU/cm²，而在0至2摄氏度的33天储存期结束时，鱼肉中的细菌计数仍<10²CFU/g。
