Irradiation is the use of ionising gamma rays emitted by cobalt-60 and caesium-137, or, high-energy electrons and X-rays to inactivate microbial pathogens, particularly in the food industry. Bacteria such as Deinococcus radiodurans are particularly resistant to radiation, but are not pathogenic. Active microbes, such as Corynebacterium aquaticum, Pseudomonas putida, Comamonas acidovorans, Gluconobacter cerinus, Micrococcus diversus and Rhodococcus rhodochrous, have been retrieved from spent nuclear fuel storage pools at the Idaho National Engineering and Environmental Laboratory (INEEL). These microbes were again exposed to controlled doses of radiation. All the species survived weaker radiation doses with little damage, while only the gram-positive species survived much larger doses. The