Coca-cola has managed to deal with this for a hundred years. Google has managed it for 10 years. These things are called trade secrets. You protect them through NDAs, being intelligent with who has access to the information, and not open-sourcing the code.
In the case of Coca-cola, at least, the secret formula isn't even much of a concern anymore (I think it's been leaked a few times actually). Them protecting the formula is really just tradition and adds to their branding. What's important to them is keeping their brand power.
