Mass. Gen. Laws ch. 128 § 58
The commissioner either in person or his assistants shall have free access at all reasonable hours to each building or other place in which commercial feeds are manufactured, processed, packed or held for distribution, or to enter any vehicle being used to transport or hold such feeds and to inspect at reasonable times and within reasonable limits and in a reasonable manner such factory, warehouse, establishment or vehicle and all pertinent equipment, finished and unfinished materials, containers, and labeling therein. The inspection may include the verification of only such records, and production and control procedures as may be necessary to determine compliance with section fifty-four.
If the officer or employee making such inspection of a factory, warehouse, or other establishment has obtained a sample in the course of the inspection, upon completion of the inspection and prior to leaving the premises he shall give to the owner, operator, or agent in charge a receipt describing the samples obtained.
If the owner of any building, factory, warehouse, or establishment, or his agent, refuses to admit the inspector or his agent, the commissioner or his deputy is authorized to obtain from the court a warrant directing such owner or his agent to submit the premises described in such warrant to inspection.
The results of all analyses of official samples shall be forwarded by the commissioner or his deputy to the person named on the label and to the purchaser. When the inspection and analysis of an official sample indicates a commercial feed has been adulterated or misbranded and upon request within thirty days following receipt of the analysis the commissioner or his deputy shall furnish to the registrant a portion of the sample concerned.
The commissioner or his deputy in determining for administrative purposes whether a commercial feed is deficient in any component, shall be guided by the official sample as defined in section fifty-one and obtained and analyzed as provided in this section.
Mass. Gen. Laws ch. 128, § 58