I love this... "you might contaminate yourself" "the thing to remember is that tobacco mold is highly toxic"
I don't think mold is why those big blocky text warnings are put on the tins.
If you have doubts about the health implications of smoking tobacco, yes throw it out. If you are immuno-suppressed, and are still smoking a pipe, I reckon you have made your choice.
And I apologize for any snark heard in the above. It is not personal. I smoke a pipe to calm the many reactionary thoughts I have. But since we are all making wild ass guesses in advance of C&D responding to this gentleman, I will throw out my own: it is packaging residue. The pictures show it all on the edge of the cake. And the statement is made that it covers the paper. My guess (I have a BS degree) is that what is shown in pictures above is transfer to tobacco from the packaging. I bet the powder is on alot of the packaging we discard. I bet it is heavier in places, like maybe the last few tin papers in the bottom of a case. Corn starch, like what is on gloves? A slip additive if they use a machine could be wax or starch?
Obviously this is not current, but at 0:21 seconds in the old C&D tour video they mention they spray the tobacco with "Mycoban". That scares me more than mold. Humans been smoking tobacco longer than we have been spraying it with "mycoban" and then smoking it... (Edited from "Micro" to avoid furthering confusion! See thread linked below. GL pEASE says Myco ban is totally great)
Mold is everywhere. We inhale it all the time. Manage your risk as you choose.