Cal. Health and Safety Code § 111200

As used in this article, the following definitions shall apply: (a) “Hamburger” means chopped fresh or frozen beef, or a combination of both fresh or frozen beef, with or without the addition of beef fat as such, and with or without the addition of seasoning. Hamburger shall not contain more than 30-percent fat, and shall not contain added water, binders, or extenders. Beef cheek meat (trimmed beef cheeks) may be used in the preparation of hamburger to the extent of 25 percent, and if in excess of natural proportions, its presence shall be declared on the label in the ingredient statement, if any, and otherwise contiguous to the name of the product. (b) “Imitation hamburger” means chopped fresh or frozen beef, or a combination of both fresh or frozen beef, with or without the addition of beef fat as such, and with or without the addition of seasoning. Imitation hamburger may contain binders and extenders, with or without the addition of partially defatted beef tissue, without added water or with added water only in amounts that the products’ characteristics are essentially that of a meat pattie. (c) “Restaurant” means restaurants, itinerant restaurants, vehicles, vending machines, or institutions including hospitals, schools, asylums, eleemosynaries, and all other places where food is served to the public for consumption on the premises of sale that are not included within the definitions of the terms restaurants, itinerant restaurants, vehicles, and vending machines.