There may have been something more than symbolic! During WWII, the brilliant chemist George Kistiakowsky (who was also at Los Alamos and developed the shaped charges needed for implosion) invented a technique to turn High Explosive into a flour like consistency that could be smuggled through the lines for use by the underground. The "flour" could also be used to make cookies, cakes and breads and that's how it often was carried in. Even better(?), these things could be eaten safely and the HE "retrieved" later.

Brings new meaning to the phrase .."Shitfire."

catspaw