Durban E, Grecz N
Appl Microbiol. 1969 Jul;18(1):44-50. doi: 10.1128/am.18.1.44-50.1969.
Spores of Clostridium botulinum 33A exhibit a sigmoidal survival curve if subjected to gamma radiation. The present investigation was concerned with two questions: (i) what is the form of an ultraviolet (UV)-survival curve and (ii) what is the combined effect of UV- and gamma radiation? The UV-survival curve was found to be of sigmoidal type with a "shoulder" width of 675 ergs/mm(2) and a D(10) (exp) of 2,950 ergs/mm(2). To test the combination effect, spores were subjected to UV doses of 225, 450, 675, and 900 ergs/mm(2) followed by a series of increasing doses of gamma rays from 200 to 2,000 krad in 200-krad steps. The gamma ray-survival curves showed that increasing UV pretreatment caused a gradual loss of the "Prodiginine" yielding straight line exponential survival curves after preirradiation with UV doses of 675 ergs/mm(2) and above. Simultaneously the D(10) value for gamma-ray irradiation was reduced, e.g. UV preirradiation with 900 ergs/mm(2) reduced the D(10) by 40%. This observation emphasizes the potential practical advantage of combining UV and gamma rays for sterilization of heat-sensitive commodities.
肉毒梭菌33A的孢子如果受到伽马辐射，其存活曲线呈S形。本研究关注两个问题：（i）紫外线（UV）存活曲线的形式是什么，以及（ii）紫外线和伽马辐射的联合效应是什么？发现紫外线存活曲线为S形，“肩部”宽度为675尔格/毫米²，D(10)（exp）为2950尔格/毫米²。为了测试联合效应，将孢子分别暴露于225、450、675和900尔格/毫米²的紫外线剂量下，随后以200千拉德的步长从200千拉德到2000千拉德施加一系列递增剂量的伽马射线。伽马射线存活曲线表明，增加紫外线预处理会导致“灵菌红素”逐渐损失，在用675尔格/毫米²及以上剂量的紫外线预辐照后产生直线指数存活曲线。同时，伽马射线辐照的D(10)值降低，例如用900尔格/毫米²的紫外线预辐照会使D(10)降低40%。这一观察结果强调了将紫外线和伽马射线结合用于热敏商品灭菌的潜在实际优势。
