Coastal Research & Extension Center, Mississippi State University, 3411 Frederic St, Pascagoula, MS 39567, USA.
Food Microbiol. 2010 Feb;27(1):109-14. doi: 10.1016/j.fm.2009.09.003. Epub 2009 Sep 15.
The main goal of this investigation was to study the efficacy of X-ray doses (0.1, 0.2, 0.3, 0.5, 0.75, 1.0, 1.5 and 2.0 kGy) on inoculated Escherichia coli O157: H7, Listeria monocytogenes, Salmonella enterica and Shigella flexneri on shredded iceberg lettuce. The second goal was to study the effect of X-ray on the inherent microflora counts and visual color of shredded iceberg lettuce during storage at 4 degrees C for 30 days. Treatment with 1.0 kGy X-ray significantly reduced the population of E. coli O157: H7, L. monocytogenes, Salmonella enterica and S. flexneri on shredded iceberg lettuce by 4.4, 4.1, 4.8 and 4.4-log CFU 5 cm(-2), respectively. Furthermore, more than a 5 log CFU reduction of E. coli O157: H7, L. monocytogenes, S. enterica and S. flexneri was achieved with 2.0 kGy X-ray. Treatment with X-ray reduced the initial microflora on iceberg lettuce and kept them significantly (p < 0.05) lower than the control during storage at 4 degrees C and 90% RH for 30 days. Treatment with X-ray did not significantly (p > 0.05) change the green color of iceberg lettuce leaves. Treatment with X-ray significantly reduced selected pathogens and inherent microorganisms on shredded iceberg lettuce leaves, which could be a good alternative to other technologies for produce (lettuce) industry.
本研究的主要目的是研究 X 射线剂量（0.1、0.2、0.3、0.5、0.75、1.0、1.5 和 2.0 kGy）对接种于冰生菜碎上的大肠杆菌 O157:H7、单核细胞增生李斯特菌、肠炎沙门氏菌和福氏志贺菌的效果。第二个目标是研究 X 射线对冰生菜碎固有微生物计数和视觉颜色的影响，这些生菜碎在 4°C 下储存 30 天。1.0 kGy X 射线处理可使冰生菜碎上大肠杆菌 O157:H7、单核细胞增生李斯特菌、肠炎沙门氏菌和福氏志贺菌的数量分别显著减少 4.4、4.1、4.8 和 4.4-log CFU/5 cm²。此外，用 2.0 kGy X 射线处理可使大肠杆菌 O157:H7、单核细胞增生李斯特菌、肠炎沙门氏菌和福氏志贺菌的数量减少超过 5 log CFU。X 射线处理可减少冰生菜碎上的初始微生物群，并使其在 4°C 和 90%相对湿度下储存 30 天时显著低于对照组（p<0.05）。X 射线处理对冰生菜叶片的绿色颜色没有显著影响（p>0.05）。X 射线处理可显著降低冰生菜碎叶上的选定病原体和固有微生物，这可能是生菜（农产品）行业其他技术的良好替代品。
