Here is an example of the typical rules (from California)

Fourteen and fifteen-year-olds may be employed in the following occupations in the food service and retail industries:

• Office and clerical work, including the operation of office machines.
• Cashiering, selling, modeling, art work, work in advertising departments, window trimming, and comparative shopping.
• Price marking and tagging by hand or by machine, assembling orders, packing and shelving.
• Bagging and carrying out customers orders.
• Errand and delivery work by foot, bicycle, or public transportation.
• Cleanup work, including the use of vacuum cleaners and floor waxers, and maintenance of grounds, but not including the use of power-driven mowers or cutters.
• Kitchen work and other work involved in preparing and serving food and beverages, including the operation of machines and devices used in the performance of this work, including but not limited to, dishwashers, toasters, dumbwaiters, popcorn poppers, milkshake blenders, and coffee grinders.
• Cleaning vegetables and fruits, and wrapping, sealing, labeling, weighing, pricing, and stocking goods when performed in areas physically separate from areas where meat is prepared for sale and outside freezers or meat coolers.