Grupo de Investigación en Alimentos de Origen Vegetal, Tecnología de los Alimentos, Universidad de Zaragoza, Zaragoza, Spain.
Food Microbiol. 2011 Feb;28(1):141-8. doi: 10.1016/j.fm.2010.09.008. Epub 2010 Sep 24.
The effects of two doses of electron-beam irradiation (1.5 kGy and 2.5 kGy) on the microbial populations (total mesophilic aerobes, Pseudomonas genus, Enterobacteriaceae family, molds and yeasts) and sensory characteristics of Tuber aestivum packaged under modified atmospheres were monitored immediately after treatment, and weekly during 42 days of storage at 4 °C. Treatment with 1.5 and 2.5 kGy reduced the pseudomonads populations by 4.3 and 5.5 logs, respectively. Enterobacteriaceae counts decreased by 5.4 logs with the 1.5 kGy dose and counts below the detection limit (<1.0 log cfu/g) were obtained with the 2.5 kGy dose. Lactic acid bacteria and yeasts were less affected by the ionizing radiation treatments and they became the dominant microbial populations throughout storage with microbial counts up to 7.1 log cfu/g. The carbon dioxide levels inside the packages containing irradiated truffles were lower than those of the non-irradiated ones, suggesting a decrease in the respiration rate of the treated ascocarps. The treatments with 1.5 and 2.5 kGy e-beam did not negatively affect the sensory characteristics of truffles, but a visible superficial yeast growth was detected in truffles irradiated with 1.5 kGy at the end of their shelf life (day 28). Treatment with 2.5 kGy e-beam has prolonged the shelf life to 42 days, compared with 21 days for the untreated samples.
辐照（1.5 kGy 和 2.5 kGy）对两种剂量下的微生物种群（总需氧嗜温菌、假单胞菌属、肠杆菌科、霉菌和酵母）和在改良气氛下包装的块菌感官特性的影响进行了监测，处理后立即进行，在 4°C 下储存的 42 天内每周进行一次。1.5 和 2.5 kGy 的处理分别使假单胞菌种群减少了 4.3 和 5.5 个对数。1.5 kGy 剂量可使肠杆菌科的计数减少 5.4 个对数，而 2.5 kGy 剂量则使计数低于检测限（<1.0 log cfu/g）。乳酸菌和酵母受电离辐射处理的影响较小，在整个储存过程中成为主要的微生物种群，微生物计数高达 7.1 log cfu/g。辐照块菌包装内的二氧化碳水平低于未辐照的包装，表明处理过的块菌的呼吸速率降低。1.5 和 2.5 kGy 的 e-射线处理没有对块菌的感官特性产生负面影响，但在辐照处理的块菌中，在货架期结束时（第 28 天）发现了可见的表面酵母生长。与未经处理的样品相比，2.5 kGy 的 e-射线处理将块菌的货架期延长至 42 天，而未经处理的样品的货架期为 21 天。
