Cal. Health and Safety Code § 113984

(a) Adequate and suitable counter space shall be provided for all food preparation operations. (b) Except as specified in subdivision (c), food preparation shall be conducted within a fully enclosed food facility. (c) Limited food preparation shall be conducted within a food compartment or as approved by the enforcement agency. Subject to subdivision (g), this subdivision does not require an additional food compartment when adding ingredients to a beverage or dispensing into a serving container when the beverage is prepared for immediate service in response to an individual consumer order. (d) Food shall be prepared with suitable utensils and on surfaces that, prior to use, have been cleaned, rinsed, and sanitized as specified in Section 114117 to prevent cross-contamination. (e) Overhead protection shall be provided above all food preparation, food display, warewashing, and food storage areas. (f) All food shall be thawed, washed, sliced, and cooled within an approved fully enclosed food facility. (g) Based upon local environmental conditions, location, and other similar factors, the enforcement officer may establish additional structural or operational requirements, or both, for mobile food facilities as necessary to ensure that foods, food-contact surfaces, and utensils are of a safe and sanitary quality.