§ 18. Rules of department. Subject and in conformity to this chapter and the constitution and laws of the state, the commissioner may enact, amend and repeal necessary rules which shall

1. Regulate and control the transaction of business by the department, provide for the exercise of the powers and the performance of the duties of the department and prescribe the powers and duties of the bureaus and of the directors of bureaus and other officers and employees thereof;

2. Provide for carrying into effect the provisions of this chapter and of the laws of the state in respect of food and food traffic;

3. Regulate the conduct of investigations, inquiries and hearings authorized by this chapter and prescribe necessary forms and notices;

4. Establish official grades for foods and farm products and prescribe the use of such grades, and provide for the marking, packing and shipping of foods and farm products so graded.

5. Establish uniform tolerances or amounts of reasonable variation for containers of food and provide uniform regulations for carrying out the provisions of this chapter in relation to such containers.

6. Provide generally for the exercise of the powers and performance of the duties of the department as prescribed in this chapter and the laws of the state and for the enforcement of their provisions and the provisions of the rules enacted as herein provided.

The rules of the department in force at the time this chapter takes effect shall continue as the rules of the department, until amended or repealed by the commissioner.