Irradiation of produce [split from SF Bay]
irradiating food basically gives it a giant cancer radiation treatment. It will kill all insects and bacteria, fungi etc on the fruit so will have some preservation properties (since everything biological that will destroy it is now dead) but is not done for that reason - it is done entirely to stop insect pests and plant diseases from being imported along with the fruit.
But like cancer treatment or an x-ray once the zapping has finished there's no residue or anything to stop something else from coming along and attacking it (which is why it isn't used to extend shelf life) and nothing harmful is left on the fruit (but it still isn't an organic treatment for reasons I'm not clear on)
Irradiation kills all insects and bacteria on and *in* the fruit. Pesticides or packaging prevent reinfestation.
It also causes chemical changes. There have been no studies of possible long-term consequences of regularly eating irradiated food, only short studies showing that there were no immediate consequences from eating it for 15 weeks.
Maybe eventually studies will show that it's as healthy as non-irradiated food, or as unhealthy as partially hydrogenated fat. We don't currently know.