No director or any other officer named in this chapter shall in any manner be interested, directly or indirectly in any contract awarded or to be awarded by the board, or in the profits to be derived therefrom; and for any violation of this provision, such officer shall be deemed guilty of a misdemeanor, and such conviction shall work a forfeiture of his or her office, and he or she shall be punished by a fine not exceeding five hundred dollars or by imprisonment in the county jail not exceeding six months, or by both fine and imprisonment: PROVIDED, That nothing in this section contained shall be construed to prevent any district officer from being employed by the district as a day laborer.