Iowa Code § 210.25: Weighing bread.

Bread when weighed for inspection shall be weighed in the manufacturer’s plant when said bread is wrapped ready for delivery, and bread coming into the state from an adjoining state when weighed for inspection shall be weighed in the packages, containers, vehicles, or trucks of the manufacturer at the time when said bread crosses the state line, or at the first point of stop for sale or delivery of said bread after crossing the Iowa state line, and the weight shall be determined by averaging the weight of not less than fifteen loaves picked at random from any given lot.