Savvaidis Ioannis N, Skandamis Panagiotis, Riganakos Kyriakos A, Panagiotakis Nikolaos, Kontominas Michael G
Department of Chemistry, University of Ioannina, Greece.
J Food Prot. 2002 Mar;65(3):515-22. doi: 10.4315/0362-028x-65.3.515.
The effect of gamma irradiation on the natural microflora of whole salted vacuum-packaged trout at 4 and 10 degrees C was studied. In addition, the effectiveness of gamma irradiation in controlling Listeria monocytogenes inoculated into trout was investigated. Irradiation at doses of 0.5 and 2 kGy affected populations of bacteria, namely, Pseudomonas spp., Brochothrix thermosfacta, lactic acid bacteria, H2S-producing bacteria typical of Shewanella putrefaciens, and Enterobacteriaceae, at both 4 and 10 degrees C. This effect was more pronounced at the higher dose (2 kGy) and the lower temperature (4 degrees C). Pseudomonads, H2S-producing bacteria typical of S. putrefaciens, and Enterobacteriaceae showed higher sensitivity to gamma irradiation than did the rest of the microbial species. Sensory evaluation did not show a good correlation with bacterial populations. On the basis of sensory odor scores, a shelf life of 28 days (2 kGy, 4 degrees C) was obtained for salted vacuum-packaged freshwater trout, compared with a shelf life of 7 days for the unirradiated sample. Under the same conditions, the growth of L. monocytogenes inoculated into the samples was suppressed by 2 log cycles after irradiation (2 kGy) and storage for up to 18 days at 4 degrees C.
研究了γ辐照对4℃和10℃下全盐真空包装鳟鱼天然微生物群落的影响。此外，还研究了γ辐照对接种到鳟鱼中的单核细胞增生李斯特菌的控制效果。0.5 kGy和2 kGy剂量的辐照在4℃和10℃下均对细菌种群有影响，这些细菌包括假单胞菌属、嗜热栖热菌、乳酸菌、腐败希瓦氏菌典型的产H2S细菌以及肠杆菌科。这种影响在较高剂量（2 kGy）和较低温度（4℃）下更为明显。假单胞菌、腐败希瓦氏菌典型的产H2S细菌和肠杆菌科比其他微生物对γ辐照更敏感。感官评价与细菌种群没有良好的相关性。根据感官气味评分，盐渍真空包装淡水鳟鱼在2 kGy、4℃条件下的货架期为28天，而未辐照样品的货架期为7天。在相同条件下，接种到样品中的单核细胞增生李斯特菌在辐照（2 kGy）后并在4℃下储存长达18天，其生长被抑制了2个对数周期。
