Bulk seeds or screenings shall be sampled by inserting a long probe or thrusting the hand into the bulk as circumstances require in at least seven uniformly distributed parts of the quantity being sampled. At least as many trierfuls or handfuls shall be taken as the minimum which would be required for the same quantity of seed or screenings in bags of a size customarily used for such seed or screenings.
7 C.F.R. §201.40