"Are commercial dried peppers irradiated or dried at a high enough temperature to kill the seeds?"

Yes in most cases. The massive commercial drying ovens are run at much higher temps than home food dehydrators as they can better control the humidity. I would think irradiation would vary from producer to producer but am not sure. And you have no way of knowing how old the dried peppers are in many cases.

Dave

PS edited to add that I know some have had success with using those peppers bought fresh.

I've had some successful sprout tests with some commercially dried peppers that I got from the local Mexican deli. Like the little tiny peppers and the thai kind of ones- but not the bigger ones. But they do have high turnover of their product, so that might have something to do with it.

Have I successfully grown out any of those peppers? Nope. I only did sprout tests to see if it was worth it to try it or not. And I have a lot of other peppers that I have gotten in trades that I want to try out more.

Thanks for the feedback you two I've still got plenty of time to start peppers for my June planting out date so I'll find a better source for these seed varieties.

I've "collected" seed from the bags of dried peppers at Walmart. The bags have holes and well, the seeds kinda fell out...
Anyway I grew out some Japones just fine. Beautiful upright pods with some good heat. That was in 2012. I just ground the last of them for powder...they were starting to fade a bit. I might try them again this season if I have room.