Any person selling or delivering eggs to restaurants, hotels, retail stores, bakeries or other institution purchasing eggs for serving to guests, patrons, employees or inmates shall furnish the purchaser with an invoice showing the name and address of the seller and the quantity, grade, and size of such eggs. If the eggs are ungraded, such fact shall appear on the invoice. A copy of such invoice shall be retained by the seller and purchaser for not less than 30 days.