Department of Food Science, Faculty of Agricultural and Food Sciences, University of Manitoba, Winnipeg, MB R2J 3L8 Canada.
Meat Sci. 2014 Jan;96(1):413-8. doi: 10.1016/j.meatsci.2013.07.034. Epub 2013 Aug 1.
This study determined the extent that irradiation of fresh beef surfaces with an absorbed dose of 1 kGy electron (e-) beam irradiation might reduce the viability of mixtures of O157 and non-O157 verotoxigenic Escherichia coli (VTEC) and Salmonella. These were grouped together based on similar resistances to irradiation and inoculated on beef surfaces (outside flat and inside round, top and bottom muscle cuts), and then e-beam irradiated. Salmonella serovars were most resistant to 1 kGy treatment, showing a reduction of ≤1.9 log CFU/g. This treatment reduced the viability of two groups of non-O157 E. coli mixtures by ≤4.5 and ≤3.9 log CFU/g. Log reductions of ≤4.0 log CFU/g were observed for E. coli O157:H7 cocktails. Since under normal processing conditions the levels of these pathogens on beef carcasses would be lower than the lethality caused by the treatment used, irradiation at 1 kGy would be expected to eliminate the hazard represented by VTEC E. coli.
本研究旨在确定用 1 kGy 电子束辐照新鲜牛肉表面的方法能在多大程度上减少 O157 和非 O157 肠出血性大肠杆菌（VTEC）和沙门氏菌混合菌的存活量。这些细菌根据辐照抗性的相似性分组，然后接种在牛肉表面（外平面和内圆形、顶部和底部肌肉切块），然后进行电子束辐照。沙门氏菌血清型对 1 kGy 处理的抗性最强，减少了≤1.9 对数 CFU/g。该处理方法使两组非 O157 大肠杆菌混合物的存活量减少了≤4.5 和≤3.9 对数 CFU/g。O157:H7 混合菌的对数减少量为≤4.0 对数 CFU/g。由于在正常加工条件下，牛肉胴体上这些病原体的水平低于处理所造成的致死水平，因此预计 1 kGy 的辐照将消除 VTEC 大肠杆菌带来的危害。
