Heating equipment shall be of a design and capacity that will enable it to bring food waste material to 212 degrees F throughout within a reasonable length of time. Occasional stirring of the garbage is required during the heating period to insure a uniform temperature. Garbage shall be held at a temperature of 212 degrees F for at least 30 minutes. The cooking container shall be equipped with a recording thermometer with one pen and one probe for each 8 feet, or portion thereof, of its length. Proposed plans for all new cooking equipment shall be approved by the Department before construction or installation is started. Cooking equipment shall be cleaned after each use.