Moini Sohrab, Tahergorabi Reza, Hosseini Seyed Vali, Rabbani Mohammad, Tahergorabi Zoya, Feás Xesús, Aflaki Fereidoon
Department of Food Science and Technology, University of Tehran, P.O. Box 31587-77871, Karaj, Iran.
J Food Prot. 2009 Jul;72(7):1419-26. doi: 10.4315/0362-028x-72.7.1419.
The effect of gamma radiation (0, 1, 3, and 5 kGy) on the shelf life of farmed rainbow trout (Oncorhynchus mykiss) fillets that were treated with sodium acetate and vacuum packaged and subsequently stored under refrigeration was studied by measuring microbiological, chemical, and organoleptic changes. Radiation affected populations of bacteria, namely, H2S-producing bacteria and Enterobacteriaceae (P < 0.05). Initial total viable counts of the control samples were ca. 4.41 log CFU/g, whereas the respective counts in samples irradiated at 1, 3, and 5 kGy were 3.08, 1.46, and < or = 1 log CFU/g at day 1 of refrigerated storage. The maximum count of Enterobacteriaceae reached 2.29 and 1.45 log CFU/g at the end of storage for 1 and 3 kGy, respectively, but at a 5-kGy dose no growth of Enterobacteriaceae was observed. Of the biochemical indicators, thiobarbituric acid values for irradiated trout were higher than for nonirradiated fish (P < 0.05). Sensory evaluation (taste) showed a reasonable and good correlation with bacterial populations with storage time. The results revealed that radiation at a high dose (5 kGy) might induce lipid and protein oxidation, although the growth of microorganisms was inhibited. Therefore, radiation at a low dose (3 kGy) could be used to control the microbial and safety biochemical indices of O. mykiss for up to 4 weeks at refrigerator temperature without adverse effects on quality and acceptability.
通过测量微生物、化学和感官变化，研究了γ辐射（0、1、3和5千戈瑞）对经醋酸钠处理、真空包装并随后冷藏保存的养殖虹鳟（Oncorhynchus mykiss）鱼片货架期的影响。辐射影响了细菌种群，即产硫化氢细菌和肠杆菌科细菌（P<0.05）。对照样品的初始总活菌数约为4.41 log CFU/g，而在冷藏储存第1天，1、3和5千戈瑞辐照样品的相应菌数分别为3.08、1.46和≤1 log CFU/g。在储存结束时，1千戈瑞和3千戈瑞处理的肠杆菌科细菌最大菌数分别达到2.29和1.45 log CFU/g，但在5千戈瑞剂量下未观察到肠杆菌科细菌生长。在生化指标中，辐照鳟鱼的硫代巴比妥酸值高于未辐照鱼（P<0.05）。感官评价（味道）显示与储存时间的细菌种群有合理且良好的相关性。结果表明，高剂量（5千戈瑞）辐射可能会诱导脂质和蛋白质氧化，尽管微生物生长受到抑制。因此，低剂量（3千戈瑞）辐射可用于在冷藏温度下控制虹鳟的微生物和安全生化指标长达4周，且对品质和可接受性无不利影响。
