Food Research Institute, Food Safety Research Division, National Agriculture and Food Research Organization, 2-1-12 Kannondai, Tsukuba, Ibaraki, 305-8642, Japan; Tsukuba Life Science Innovation, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki, 305-8577, Japan.
Food Research Institute, Food Safety Research Division, National Agriculture and Food Research Organization, 2-1-12 Kannondai, Tsukuba, Ibaraki, 305-8642, Japan.
Food Microbiol. 2019 Apr;78:110-113. doi: 10.1016/j.fm.2018.10.011. Epub 2018 Oct 22.
Irradiation of ground beef and beef liver inoculated with Escherichia coli O157 466 and DT66 and Salmonella Enteritidis 3313 were performed with gamma rays from cobalt-60 at refrigerated and frozen temperatures under air- and vacuum-packaged conditions. Results showed that D values for all pathogens in frozen beef liver were higher than those in frozen ground beef samples, with significant differences observed between the D values of E. coli O157 466 and S. Enteritidis 3313 under air-packaged conditions, as well as in E. coli O157 DT66 and S. Enteritidis 3313 under vacuum-packaged conditions. To verify effective bacterial inactivation under high bacterial-contamination levels (10-10 CFU/g), survival/death interfaces of E. coli O157 DT66 and S. Enteritidis 3313 inoculated in beef liver under vacuum-packaged and frozen conditions were constructed, with results suggesting that doses from 5.3 kGy to 5.5 kGy and 8.2 kGy-8.5 kGy would be sufficient to kill 10 CFU/g of E. coli O157 and S. Enteritidis 3313, respectively, at a 95%-99% predicted confidence interval. These results suggested that food matrixes containing high amounts of antioxidants (such as beef liver) and treated under frozen and vacuum-packaged conditions require additional consideration and evaluation for applications of irradiation treatment.
将大肠杆菌 O157 466 和 DT66 以及肠炎沙门氏菌 3313 接种到地面牛肉和牛肝中，然后用钴-60 产生的伽马射线在冷藏和冷冻温度下，在空气和真空包装条件下进行照射。结果表明，所有病原体在冷冻牛肝中的 D 值均高于冷冻碎牛肉样本，在空气包装条件下，大肠杆菌 O157 466 和肠炎沙门氏菌 3313 的 D 值之间以及在真空包装条件下，大肠杆菌 O157 DT66 和肠炎沙门氏菌 3313 之间存在显著差异。为了验证在高细菌污染水平（10-10 CFU/g）下的有效细菌灭活，构建了真空包装和冷冻条件下牛肝中接种的大肠杆菌 O157 DT66 和肠炎沙门氏菌 3313 的存活/死亡界面，结果表明，5.3 kGy 至 5.5 kGy 和 8.2 kGy-8.5 kGy 的剂量足以在 95%-99%的预测置信区间内杀死 10 CFU/g 的大肠杆菌 O157 和肠炎沙门氏菌 3313。这些结果表明，含有大量抗氧化剂的食物基质（如牛肝）在冷冻和真空包装条件下处理时，需要额外考虑和评估辐照处理的应用。
