IN the early 1930's, Rabbi Tobias Geffen of Congregation Shearith Israel in Atlanta approached Harold Hirsh, an attorney for the Coca-Cola Corporation, and told him he had to know what ingredients were in the "secret recipe" to certify the drink's kosher status. Sworn to secrecy about the recipe, Geffen in 1935 published a teshuva, or Jewish legal response, affirming Coca-Cola's kosher certification for Passover. "With the help of God," wrote Geffen, "I have been able to uncover a pragmatic solution according to which there would be no question or any doubt concerning the ingredients of Coca-Cola."
http://vosizneias.blogspot.com/2005/09/is-coke-kosher.html
http://vosizneias.blogspot.com/2005/09/is-coke-kosher.html