is there any truth to the idea that if cook something with mayonnaise on it in the microwave oven the mayonnaise will
go bad and make you sick.

I routinely do so, and I haven’t been sick yet. Of course, I’m the same guy who’s wife’s going to kill him by leaving beans and meatballs out overnight.

From what I heard on THAT thread, it’ll go bad if you don’t eat it or refrigerate it right away. On the other hand, only in movies does microwave exposure cause big germs to biggie-size and multiply rapidly, so you’re probably okay.