Section 13E. Boards of health of cities and towns may adopt bacterial standards for milk which are numerically less but not greater than such standards as may be established therefor under sections twelve and thirteen. Rules and regulations promulgated under said sections shall not be construed to prevent the exercise by such boards of the powers and duties conferred and imposed upon them by section forty-one nor to prevent the sale of milk the production of which is regulated under authority of sections twenty to twenty-five, inclusive, of chapter one hundred and eighty. This section shall not be deemed to authorize the sale or delivery of milk, cream or products thereof which are not in compliance with applicable rules and regulations established pursuant to said sections twelve and thirteen.