(a) Except as otherwise provided in this part, the Secretary shall limit the shipment of onions by any one or more of the methods hereinafter set forth whenever he finds from the recommendations and information submitted by the committee, or from other available information, that such regulation would tend to effectuate the declared policy of the act. Such limitation may:

(1) Regulate in any or all portions of the production area, the handling of particular grades, sizes, or qualities of any or all varieties of onions, or combinations thereof, during any period or periods;

(2) Regulate the handling of particular grades, sizes, or qualities, of onions differently, for different varieties, for different portions of the production area, for different packs, or for any combination of the foregoing, during any period or periods;

(3) Provide a method, through rules and regulations issued pursuant to this part, for fixing the size, capacity, weight, dimensions, or pack of the container, or containers, which may be used in the packaging or handling of onions, including appropriate container markings to identify the contents thereof;

(4) Regulate the handling of onions by establishing, in terms of grades, sizes, or both, minimum standards of quality and maturity; or

(5) Limit the shipment of the total quantity of onions by prohibiting the handling thereof during a specified period or periods. No regulation issued pursuant to this subparagraph shall be effective for more than 96 consecutive hours: Provided, That not less than 72 consecutive hours shall elapse between the termination of any such period of prohibition and the beginning of the next such period.

(6) Regulate the handling of onions by establishing, in terms of total weight or total number of layers of containers of onions, the maximum load in railcars, taking into account types of containers and sizes of railcars used, potential resulting damage, and other relevant factors.

(b) In the event the handling of onions is regulated pursuant to paragraph (a)(5) of this section, no handler shall handle any onions which were prepared for market or loaded during the effective period of such regulation. However, during any such period, no such regulation shall be deemed to limit the right of any person to sell or contract to sell onions for future shipment or delivery.

(c) The Secretary may amend any regulation issued under this part whenever he finds that such amendment would tend to effectuate the declared policy of the act. The Secretary may also terminate or suspend any regulation or amendment thereof whenever he finds that such regulation or amendment obstructs or no longer tends to effectuate the declared policy of the act.