Department of Food Science, Faculty of Agricultural and Food Sciences, University of Manitoba, Winnipeg, Manitoba, Canada R2J 3L8.
J Food Prot. 2013 Aug;76(8):1438-42. doi: 10.4315/0362-028X.JFP-12-492.
Verotoxigenic Escherichia coli (VTEC) and Salmonella are major foodborne pathogens, but very little information is available on the radiation resistance of a sufficiently diverse group of these pathogens. The objective of this study was to evaluate the sensitivity of E. coli O157:H7, non-O157 VTEC, and Salmonella to a low-dose ionizing radiation treatment. Test organisms were 6 serovars of Salmonella, 5 strains of E. coli O157:H7, and 27 strains of non-O157 VTEC (representing 19 serotypes). Decimal reduction doses (D-values) for individual strains were determined in phosphate-buffered saline using an X-ray source. The viability of the bacterial cells declined with an increase in absorbed dose from 0 to 0.3 kGy. The more resistant test strains were screened at 0.5 and 0.7 kGy. All six Salmonella strains survived at 0.5 and 0.7 kGy; however, only 11 VTEC survived at 0.7 kGy. After the 0.3-kGy treatment, both E. coli O157:H7 and non-O157 VTEC had D-values with similar means and ranges (0.028 to 0.123 and 0.037 to 0.127 kGy, respectively), with no significant differences (P > 0.05). Salmonella strains had a slightly higher range of D-values (0.061 to 0.147 kGy) and a mean D-value that was significantly higher (P > 0.05) than that of both the E. coli O157:H7 and non-O157 VTEC groups.
产肠毒素性大肠杆菌（VTEC）和沙门氏菌是主要的食源性病原体，但关于这些病原体的足够多样化群体的辐射抗性的信息非常少。本研究的目的是评估大肠杆菌 O157:H7、非 O157 VTEC 和沙门氏菌对低剂量电离辐射处理的敏感性。试验菌为 6 种血清型沙门氏菌、5 株大肠杆菌 O157:H7 和 27 株非 O157 VTEC（代表 19 种血清型）。使用 X 射线源在磷酸盐缓冲液中确定各菌株的十进制减少剂量（D 值）。细菌细胞的存活率随着吸收剂量从 0 增加到 0.3 kGy 而下降。在 0.5 和 0.7 kGy 下筛选更具抗性的试验菌株。所有 6 株沙门氏菌均在 0.5 和 0.7 kGy 下存活；然而，只有 11 株 VTEC 在 0.7 kGy 下存活。经过 0.3 kGy 处理后，大肠杆菌 O157:H7 和非 O157 VTEC 的 D 值具有相似的平均值和范围（分别为 0.028 至 0.123 和 0.037 至 0.127 kGy），没有显著差异（P > 0.05）。沙门氏菌株的 D 值范围略高（0.061 至 0.147 kGy），平均值明显高于大肠杆菌 O157:H7 和非 O157 VTEC 组（P > 0.05）。
