Section 16L. Whoever sells, exchanges or delivers, or has in his possession with intent to sell, exchange or deliver, milk shipped into the commonwealth from a milk plant, receiving station or pasteurization plant which has not been inspected and approved, or to which a permit has not been issued as provided in section sixteen K, shall be punished for a first offence by a fine of not less than five hundred nor more than one thousand dollars, for a second offence by a fine of not less than one thousand nor more than five thousand dollars, and for a subsequent offence by a fine of five thousand dollars and by imprisonment for not less than six months. This section shall not apply to any sale, exchange or delivery of milk brought into the commonwealth under a temporary permit issued under section sixteen H.