Ohio Rev. Code § 919.07: Sign to be displayed by establishment.

No proprietor, manager, or person in charge of a meat market, hotel, restaurant, lunchroom, cafeteria, or eating house, industrial, fraternal, educational, or otherwise, in which meals are served to the public, shall therein sell, serve, or use in cooking for consumption by the public, on or off the premises, horse meat or horse meat food products, without posting a sign in a conspicuous place, which shall be white and not less than twelve by eighteen inches in size, upon which shall be printed in plain black Roman letters, "Horse Meat Sold Here" or "Horse Meat Served Here," whichever is applicable.