Massachusetts General Laws Part I. Administration of the Government (Ch. 1-182) Ch. 138, § 63

The local licensing authorities or their agents may at any time enter upon the premises of a person who is licensed by them, and the commission or its agents may enter upon the premises of any holder of a license, permit or certificate of fitness under this chapter, to ascertain the manner in which he conducts the business carried on under such license, permit or certificate. Such licensing authorities or their agents may at any time take samples for analysis from any beverages or alcohol kept on such premises, and the vessel or vessels containing such samples shall be sealed on the premises in the presence of the holder of such license, permit or certificate or one of his employees, and shall remain so sealed until presented to the state department of public health for analysis, and duplicate samples shall be left with such holder.