You definitely need to keep your restaurant's recipes secret.
Stealing recipes is a time-honored tradition for home cooks and professionals alike.
One need only peruse the world of food bloggers for five minutes to discover just how many people have an "original" recipe for chocolate chip cookies that varies by about 4 teaspoons of sugar or two minutes of cooking time. With so many people out there ready and willing to take credit for other chefs' work, many restaurateurs and food industry pros are naturally curious about what they can do to protect their original creations.
Here's the thing: It is possible to patent food products and to trademark food names, but the constraints are very narrow and don't apply to the types of foods sold in most independent restaurants.
How to patent a recipe
A recipe may be successfully patented if it meets several criteria. First, the recipe in question must be novel. That means it cannot be a food item previously familiar to the public or an obvious combination of pre-existing food items. For example, if you decide to take brownies and chocolate chip cookies, and mix them with coffee ice cream for a flavor called Coffee Brownie Chip, you'll have a tough time getting that patented. The reason is that, even if no one else has sold that exact combination before, the notion of combining candy and cookies into ice cream is well-trodden territory, and therefore it's not a novel product. If it's possible for a fellow chef to taste your recipe and discern what's in it and how it was made, that's a surefire sign your recipe isn't novel enough for a patent.
Now, if you found a way to make Coffee Brownie Chip ice cream with a totally unique food formulation or process, like by using spinach instead of milk and cream, or by freezing it in a way that's never been done before (if you invented the freezing process used, for example), you have a better shot at getting a patent. Remember, a patent is for the protection of an original invention, so your recipe can't just be the best barbecue sauce ever – it must be something that breaks the mold in terms of formulation or process, or both.
These guidelines make it difficult, bordering on impossible, to protect recipes under patent law unless you are part of a food science lab, backed by a large food corporation, or part of a powerful chain or franchise. For most independent food retailers, restaurants, cafes, bakeries and boutique food companies, there's no point in even trying to get a patent.
Trademarking a recipe
While patenting a recipe is extremely difficult, it is possible to trademark a recipe or food item for branding purposes. Trademarking the name of a food item won't prevent someone from stealing, recreating or selling your recipe, but it will prevent the competition from advertising it by the same name. This is evident in the proliferation of "dupe" recipes online. It's not illegal for a chef to figure out how a popular soda is made and then publish the recipe, or even make it herself and sell it in her restaurant. However, she cannot call the soda by the name it goes by on the grocery store shelves, because that name is trademarked.
Fast food and chain restaurants are great at the trademarking approach, but it can work for smaller businesses as well. In many cases of trademarked foods, the trademarked name eventually becomes more powerful than the food item itself. Anyone can cook a processed frozen burger, slap on some dehydrated onions and sell it, but only one restaurant in the world can legally serve a Big Mac.
What to do if you can't patent or trademark
You've probably heard the term "trade secret" before, and it's probably the oldest and most effective way of protecting original recipes, but it isn't legally binding. A trade secret essentially means that you have developed an internal system for maintaining secrecy, without legal recourse if things go wrong. The key to maintaining a trade secret is having a trustworthy staff and staying tight-lipped about the secret ingredients and cooking processes for your best sellers.