The commission shall appoint a shipper advisory committee of five members appointed from shippers at large to advise the commission on the exercise of its powers and duties under this chapter. Such members shall be natural persons, each of whom shall be citizens and residents of this state, over the age of 25 years, each of whom, as an individual, partner or employee of a shipper or shippers, is and has been actively engaged in shipping fresh grapes in this state for a period of at least five years.