7 C.F.R. § 1000.4 – Plant.

(a) Except as provided in paragraph (b) of this section, plant means the land, buildings, facilities, and equipment constituting a single operating unit or establishment at which milk or milk products are received, processed, or packaged, including a facility described in paragraph (b)(2) of this section if the facility receives the milk of more than one dairy farmer.
(b) Plant shall not include:
1. (1) A separate building without stationary storage tanks that is used only as a reload point for transferring bulk milk from one tank truck to another or a separate building used only as a distribution point for storing packaged fluid milk products in transit for route disposition; or
2. (2) An on-farm facility operated as part of a single dairy farm entity for the separation of cream and skim or the removal of water from milk.