(a) The terms of this subchapter shall not apply to flour or bread which is made from the entire wheat berry with no parts of the wheat removed from the mixture. In cases of flour or bread containing mixtures of the whole wheat berry and white flour or mixtures of various portions of the wheat berry, the products shall have a vitamin and mineral potency at least equal to enriched flour or enriched bread as described in this subchapter.
(b) The terms of this subchapter shall not apply to flour ground for the wheat producer whereby the miller is paid in wheat or feed for the grinding service rendered, except insofar as the mill may manufacture tollwheat into flour and sell or offer for sale the flour, whereupon this subchapter shall be applicable.
(c) The provisions of this subchapter shall not apply to farmers exchanging their wheat for flour or having the wheat ground into flour and disposing of the wheat for their own use or for the use of farm labor on their farms.