Feb. 15, 2011 -- The public radio program "This American Life" went on the air this weekend claiming to have unearthed the notoriously closely guarded secret formula for Coca-Cola.

"I am not kidding," host Ira Glass said at the top of the show, rustling the paper into his microphone. "One of the most famously guarded trade secrets on the planet: I have it right here and I am going to read it to you. I am going to read it to the world."

Glass goes on to spend the first half of his program explaining how he found the recipe, hidden in plain view.

His story starts when he stumbled across a column in the Feb. 18, 1979, edition of the Atlanta-Journal Constitution, Coke's hometown paper. There, "buried" on page 2B was a photograph of a page from an old book of handwritten pharmacists' recipes.

Coca-Cola was invented in the 1880s by John Pemberton, a pharmacist, and was originally sold at drug store soda fountains.

Glass also talked to author Mark Pendergrast, who claims to have found the original Coca-Cola recipe in Coke's archives while researching his 1993 expose, "For God, Country & Coca-Cola."

The two formulas are remarkably similar, leading Glass to conclude that he had, indeed, uncovered the original recipe. He had a batch made up at the Jones Soda Co. in Seattle.

It didn't taste exactly like the Coke we know today because, in part, at least one ingredient is almost impossible for anyone but Coca Cola to obtain: fluid extract of coca, which are coca leaves that have been stripped of cocaine. (Coke has a special arrangement with the Drug Enforcement Administration, which allows the company to import the leaves, Glass said. And there's only one factory in the country that processes the leaves exclusively for the company.)

The rest of the recipe includes citric acid, caffeine, sugar, water, lime juice, vanilla, and caramel. A second part of the formula, which had the code name "7X," contains alcohol, orange oil, lemon oil, nutmeg oil, coriander, neroli and cinnamon.

For its part, Coca-Cola is not sweating.

"Many third parties have tried over time to crack our secret formula," spokeswoman Kerry Tressler told ABC News. "Try as they might, there's only one real thing. And that was not it."

Coke Isn't The Only One With a Secret

Even still, Glass's find is tantalizing, prompting an examination of what other secret corporate recipes -- edible and otherwise -- remain uncracked codes. A brief rundown:

Big Mac Special Sauce, McDonald's. The Big Mac sauce didn't become ubiquitously known until 1975, when a canny advertiser incorporated the phrase "special sauce" into the iconic burger's jingle. (All together now: "Two all-beef patties, special sauce, lettuce cheese ... ") The spread, which bears a striking resemblance to Thousand Island dressing, is delivered to McDonald's restaurants in sealed canisters designed by Sealright.

KFC Chicken. After being locked in a safe for nearly seven decades, the Colonel's original handwritten recipe of 11 herbs and spices was temporarily relocated to a more secure location, transported in an armored car. It is alleged that only two KFC executives know the entirety of Colonel Harland Sanders' finger-lickin' recipe. Components of the mix are assembled at different locations to ensure security.

Mrs. Fields Cookies. It has become the stuff of urban legend: In the late 1980s, a chain mail started circulating, purporting to contain the secret recipe for Mrs. Fields chocolate chip cookies, purchased for $250. Debbi Fields actually posted a reply in all of her stores: "Mrs. Fields recipe has never been sold. ... Mrs. Fields recipe is a delicious trade secret."

Similar mail schemes have bedeviled Waldorf-Astoria hotel's red velvet cake and Neiman Marcus' own chocolate chip cookies.

Twinkies. As Steve Ettlinger watched his daughters gleefully munch on Hostess Twinkies one day, he decided to read the ingredients. Horrified by the mumbo jumbo he saw on the packaging, he decided to decode the ingredients. The result -- "Twinkie, Deconstructed" -- chronicles Ettlinger's journey to discover the source of every listed ingredient.

According to Ettlinger, Interstate Bakeries Corp., which makes Twinkies, didn't exactly cooperate with his research.

Krispy Kreme Donuts. The Winston-Salem, N.C., doughnut company sued the operators of one of its own stores last year on a claim that they deviated from the top-secret recipe when they ran out of the ingredients. "Only a very limited number of Krispy Kreme employees have access to the recipe," which is kept in a safe at the company's headquarters, the company claimed in its suit.

The famous confectioner got its start in 1937 when Vernon Rudolph bought a secret yeast-raised doughnut recipe from a French chef in New Orleans.

WD-40. What makes the super-lubricant so lubricated? It has long been a closely guarded trade secret. Indeed, the product has never been patented in order to avoid having to completely disclose its ingredients.

Developed in 1953 by Norm Larsen, founder of the Rocket Chemical Co., San Diego, Calif., WD-40 was originally designed to repel water and prevent corrosion. He perfected his secret formula, which is locked away in a bank vault, on his 40th attempt.

Taco Bell's Beef. This is one secret that was never intended to get out. A California woman sued Taco Bell earlier this year, claiming its taco filling is only 35 percent ground beef. The rest, she alleges in her class action suit, consists of edible padding: binders, extenders, preservatives, additives and other non-meat ingredients.

Taco Bell claims its filling is 88 percent ground beef. Even so ... what's the other 12?