Dept. of Animal Science, Texas A&M Univ., College Station, TX 77843-2471, USA.
J Food Sci. 2010 Aug 1;75(6):S319-26. doi: 10.1111/j.1750-3841.2010.01664.x.
The use of ionizing radiation for the control of foodborne pathogens and extending the shelf life of fresh iceberg lettuce and fresh spinach has recently been approved by the U.S. Food and Drug Administration. The efficacy of electron beam irradiation for controlling foodborne pathogens has been reported. For this experiment, the effectiveness of electron beam irradiation on the microbiological and sensory characteristics of fresh spinach was studied. Total aerobic plate counts were reduced by 2.6 and 3.2 log CFU/g at 0.7 and 1.4 kGy, respectively. Lactic acid bacteria were reduced at both doses of e-beam but grew slowly over the 35 d of the experiment. Yeasts and molds were not reduced in samples exposed to 0.7 kGy whereas 1.4 kGy significantly reduced microbial counts. Gas compositions (O(2) and CO(2)) were significantly different than controls. Oxygen levels inside the spinach sample bags decreased over time; however, O(2) levels did not drop below 1% that can induce anaerobic fermentation. CO(2) levels for all treatments increased through day 4; yet 7 d after irradiation, CO(2) level differences were not significant in both control and irradiated samples. Irradiation dose did not affect the basic tastes, aromatics, or mouth feels of fresh spinach, however; hardness attributes decreased as irradiated dose increased and slimy attributes of fresh spinach were higher in control samples compared to irradiated samples.
最近，美国食品和药物管理局批准了使用电离辐射来控制食源性病原体并延长新鲜冰山生菜和新鲜菠菜的保质期。已经报道了电子束辐照控制食源性病原体的功效。在这项实验中，研究了电子束辐照对新鲜菠菜微生物学和感官特性的影响。总需氧平板计数在 0.7 和 1.4 kGy 时分别降低了 2.6 和 3.2 个对数 CFU/g。在两个电子束剂量下，乳酸菌都减少了，但在实验的 35 天内生长缓慢。在暴露于 0.7 kGy 的样品中，酵母菌和霉菌没有减少，而 1.4 kGy 则显著减少了微生物计数。气体成分（O2 和 CO2）与对照组明显不同。菠菜样品袋内的氧气水平随时间推移而降低；然而，O2 水平没有降至 1%以下，这会引起厌氧发酵。所有处理的 CO2 水平在第 4 天都有所增加；然而，在辐照后 7 天，对照和辐照样品中的 CO2 水平差异不显著。辐照剂量并未影响新鲜菠菜的基本味道、香气或口感，但随着辐照剂量的增加，硬度属性下降，且与辐照样品相比，新鲜菠菜的粘稠属性在对照样品中更高。
