KFC Confidential

It's one of the closest guarded secrets in America. Now, as Kentucky Fried Chicken tightens security further, Emma Cowing discovers the obsessive measures being taken to keep the famous recipe firmly under wraps

ON TUESDAY morning, in the Kentucky town of Louisville, a top-secret security operation took place. Deep inside a company headquarters, an unidentified person known only as a "keeper" carefully opened a vault. Behind it lay a door with three locks, which he gently opened. Behind that sat a simple filing cabinet equipped with two combination locks. As the keeper opened the final door to reveal the reason for all this secrecy, the smell that met the air was strong, sweet and overpowering. It was the unmistakable smell of Kentucky Fried Chicken.

The original recipe for Kentucky Fried Chicken, a single sheet of yellowing notebook paper covered in the messy handwritten scrawl of Colonel Harland Sanders, who scratched it out himself in 1940 at his tiny restaurant in south-eastern Kentucky, is on the move. For more than 20 years it has been kept tucked away in the same filing cabinet in the company's HQ, along with vials of the herbs and spices used in the recipe. Only two keepers hold the keys to the recipe at any one time (the company even uses different suppliers for the recipe's ingredients, so no-one knows exactly what is being used), and security is tight.

But not, KFC has decided, quite tight enough. So on Tuesday, the recipe, retrieved by one of its keepers, was placed in a lockbox handcuffed to security expert Bo Dietl, a former New York City police detective, who was whisked away in an armoured car escorted by off-duty police officers to an undisclosed location, while some security modifications were made to its usual home.

"I don't want to be the president who loses the recipe," KFC's president, Roger Eaton, says by way of explanation. "Imagine how terrifying that would be."

Indeed. Because, while KFC may not be to everyone's taste (as comedian Jack Dee once remarked, "what sort of family eats their dinner out of a bucket?"), and is unlikely ever to win any awards for healthy eating – it is still one of America's most famous foods, rivalled only by McDonald's for worldwide fame but with a more homespun feel, thanks to its iconic figurehead, the colonel. No man with a white beard bar Santa Claus, is more internationally recognised.

Though Sanders died in 1980, his image still adorns all KFC branding and packaging, while older Americans will remember the Colonel himself appearing on television commercials telling viewers that his chicken was "finger lickin' good". The company, which in 1997 renamed itself KFC (sparking an urban myth that the company was using chicken so genetically modified it could no longer be called "chicken") last year started using its full title again, another nod to its traditional roots.

This latest and well-publicised move is probably also part of the firm's efforts to appear a caring Southern company – the firm's TV adverts all use an adapted version of Lanyard Skynyrd's Sweet Home Alabama, despite the firm's Kentucky connections.

Over the years rival fired chicken firms have tried to replicate the recipe, and occasionally someone claims to have found a copy of Sanders' creation, while various websites publish their own version of the recipe.

Devin Alexander is a chef and food writer who specialises in replicating healthier versions of fast food dishes in her cookbook Fast Food Fix, and says she found it easy to crack the KFC code by seasoning a skinless chicken breast with sugar, salt, pepper, onion powder and paprika before coating it with a breading that is two parts Japanese panko breadcrumbs to one part normal breadcrumbs. "They taste just as good as the original," she says.

However, the company maintains that no-one has ever come close to replicating its secret flavouring. Larry Miller, a restaurant analyst with RBC Capital Markets, remarks that the recipe's value was "almost an immeasurable thing. It's part of that important brand image that helps differentiate the KFC product."

And KFC is not the only company with a secret recipe under lock and key. Coca Cola adopts a similar cloak-and-dagger approach to its famous beverage, as does Mars about the exact contents of the Mars bar, and McDonald's about exactly what goes into in a Big Mac (some of us would prefer not to know). The makers of Drambuie meanwhile, Scotland's popular liquor, also maintain its recipe is secret, allegedly given to a member of the McKinnon family by Bonnie Prince Charlie in return for allowing him to hide with them, and passed down through the family ever since.

But, whatever is in these recipes, and even if the hype is little more than a publicity stunt, there's something comforting about knowing that some of the world's biggest food producers still keep their favourite recipes in a handwritten scrawl. Even if it is in a locked, guarded vault.