The department shall fix the compensation of its officers and employees, other than those of wardens and clerks, at a gross rate which shall include a cash allowance for board and lodging, but in no case shall the money compensation, exclusive of the cash allowance for board and lodging, be less than one hundred ten dollars ($110) per month. There shall be deducted from the gross salaries of the officers and employees of the prison the value of any board, lodging, services or supplies rendered or sold to each such officer or employee. The deduction for board and lodging shall not exceed the cash allowance therefor.