Section 29. The director shall be responsible for timely dissemination of information to all persons licensed by him under prior provisions of earlier law or certified by him under the provisions of either section twenty-seven or section twenty-seven A with respect to technical developments and improved procedural methods pertinent to their operations and may, in his discretion, require additional evidence of competency for continued licensing or certification. He or his agent may enter upon any premises, including bulk tank trucks, where samples of milk or cream are taken, stored or tested in order to inspect any utensil, device or equipment used in making tests or to ascertain the continuing competency of any person so licensed or certified, and shall report to the said chief of the bureau of milk marketing any violation observed by him of the provisions of sections twenty-five through twenty-eight A or of the rules and regulations issued under the provisions of section twenty-nine A. He shall also be represented at any hearing held as provided in section twenty-nine A and shall enter testimony thereat with respect to such proposals for amendment of rules and regulations as may be under consideration.