The only cereal sponsoring a radio serial that I remember at the moment was Wheaties for "Jack Armstrong, the All-American Boy" but I think there were a few other cereal sponsors for radio serials.
This little play on my words popped into my conscious mind when I was thinking about the title of the Italian podcast, "Fuori Tempi", which means Outside Times, but I'm not sure what that means. I'll probably find out when I get around to listening to it. The title made me think of the phrase "fuori serie" that means a special car model that is not in a companies usual line.