Section 189. Examination of samples of food, drugs, cosmetics and devices, in order to determine by analysis or test whether such articles are adulterated or misbranded within the meaning of section one hundred and eighty-six to one hundred and ninety-five, inclusive, shall be made under the direction and supervision of the department taking such samples as provided in the preceding section; and if it shall appear from such examination that any of the samples are so adulterated or misbranded, the commissioner of public health need not cause formal complaint to be entered at once, but shall in the case of misbranding, and may in the case of adulteration, cause reasonable notice thereof, together with a copy of the results of such analysis or test, to be given to the party from whom the sample was obtained or to the party believed to be responsible for the condition of the sample, to the guarantor, if any, and to the party, if any, whose name appears upon the label as manufacturer, packer, producer, wholesaler, retailer or other dealer. Before any formal complaint is entered, any person so notified shall be given an opportunity to be heard before any person designated by the commissioner of public health, under such rules and regulations as the department of public health prescribes. Such notice shall specify the date, hour and place of hearing, and the parties interested therein may appear in person or by attorney. If it is decided that the party whose name appears upon the label, or the guarantor, shall be notified, and such party or guarantor resides without the commonwealth, the notice shall be sent by mail to such address as, with due diligence, may be obtained. If after such opportunity to be heard it appears that any provision of sections one hundred and eighty-six to one hundred and ninety-five, inclusive, has been violated the commissioner of public health may make or authorize to be made a formal complaint to a court or justice having jurisdiction in such cases, but no evidence of the result of such analysis or test shall be received if the agent described in the preceding section has refused or neglected to seal and deliver the sample, or part thereof, if and as required in the preceding section. In the case of food, local boards of health shall have the same authority as the commissioner of public health.