Whenever the Committee deems it advisable to establish grade or size requirements for any variety of dates, in addition to the minimum standard provided pursuant to § 987.39, to govern dates of such variety to be handled in any designated outlet or to be withheld to meet withholding obligation, or both, it shall recommend to the Secretary requirements as to grade based on the effective United States Standards for Grades of Dates or any modification thereof, and such size requirements as it may deem appropriate. If the Secretary finds, upon the basis of such recommendation or other information available to him, that such additional grade or size regulation, or both such regulations, will tend to effectuate the declared policy of the act, he shall establish such regulations. Notice thereof, showing the effective date, shall be sent by the Committee to all handlers of record. On and after the effective date no handler shall handle dates of such variety in any designated outlet or withhold such dates to meet withholding obligation except in accordance with such regulations.