Section 19. (a) Each notice of a general hearing and each general order, rule or regulation adopted by the commissioner, shall be published by

(1) Posting a copy thereof for public inspection in the main office of the commissioner;

(2) Mailing a copy thereof, postage prepaid, addressed to each licensee deemed by the commissioner to be affected thereby at his principal business address in the commonwealth as appearing in the records of the commissioner, and to the clerk of each city and town, and to the county agricultural agent, if any, of each county, deemed by the commissioner to be affected thereby;

(3) Mailing a copy thereof, postage prepaid, addressed to each person who has filed with the commission a written request, upon a form approved by the commissioner and supplied by the director, that a copy of each notice of general hearing and of each general order, rule or regulation affecting a specified market or markets be mailed to him at an address given in such form of request; and

(4) Mailing, postage postpaid, or delivering a copy thereof, and in the case of an order, rule or regulation, a copy of a release relative thereto, to: state house press room, state house news service, any news reporting service which has filed with the commissioner written request for a copy of each notice of general hearing and general order, rule or regulation issued by the commissioner, and such other newspaper or newspapers published or circulating in the market or markets affected as in the judgment of the commissioner will afford sufficient notice and publicity thereof; and

(5) In the case of each notice of general hearing, also by advertisement in such newspaper or newspapers as, in the judgment of the commission, will afford sufficient notice to the public thereof.

(b) A general order, rule or regulation duly adopted by the commission, posted and published as provided by subsection (a) of this section shall, upon being filed with the state secretary as required by section thirty-seven of chapter thirty, have the force and effect of law. A copy of any such general order, rule or regulation certified by the state secretary to have been filed in his office shall be received in proceedings before any court or before the commissioner as prima facie evidence that such order, rule or regulation was duly adopted, posted, published and filed as required by law.

(c) Each notice of a special hearing, each subpoena and each special order, rule or regulation applying only to one or more persons named therein, issued by the commissioner, shall be served on the person or persons affected, by

(1) Mailing by registered mail, postage prepaid, an attested copy thereof addressed to each applicant or licensee affected, at his principal business address in the commonwealth as appearing in the records of the commissioner, and to each other person affected thereby at his last known address; or

(2) Delivering such a copy in hand to, or leaving such a copy at the last and usual place of abode in the commonwealth of, each individual affected thereby, and, in the case of service of a notice or special order, rule or regulation on a corporation, by delivering such a copy to the president, treasurer, clerk, cashier, secretary, agent or other officer in charge of its business, or, if no such officer is found, by leaving such a copy at its principal office or place of business within the commonwealth.

(d) Service by delivery of an attested copy pursuant to subsection (c) of this section may be made by any employee of the department, at any place within the commonwealth, or by any constable or other officer authorized to serve civil process at the place of delivery, or, in the case of a subpoena, by any disinterested person. The verified return by the individual delivering any such copy setting forth the manner of such service, or the return post office receipt therefore when mailed by registered mail shall be proof of service of the same.