Cal. Food & Agric. Code § 5323

This division and the regulations which are established pursuant to this division are of a statewide interest and concern and are intended to occupy the field. No local jurisdiction shall adopt ordinances, laws, or regulations which prevent, hinder, or delay the effect or application of this division or regulations established pursuant to this division. Regulations established pursuant to this division are not valid unless they are clearly consistent with a strict interpretation of this division and are necessary to effectuate the purpose of this division. The adoption of the regulations does not create any presumption of their necessity or validity.