A copy of the recipe, signed by Sanders, is held inside a safe inside a vault in KFC's Louisville headquarters, along with eleven vials containing the herbs and spices.[14][15] To maintain the secrecy of the recipe, half of it is produced by Griffith Laboratories before it is given to McCormick, who add the second half.[16]
In 1983, William Poundstone conducted laboratory research into the coating mix, as described in his book Big Secrets, and claimed that a sample he examined contained only flour, salt, monosodium glutamate and black pepper.[17] KFC maintains that it still adheres to Sanders' original 1940 recipe.[18] In Todd Wilbur's television program Top Secret Recipe, the Colonel's former secretary, Shirley Topmiller, revealed that Sanders learned from his mother that sage and savory are good seasonings for chicken.[19] Also, Winston Shelton, a former friend of the Colonel, said that the secret recipe contains Thalassery black pepper.[19]