This is a very interesting thread to read. As an artist and Fine Arts & Illustration professor, being knowledgeable about Copyright & Fair Use, Creative Commons, Public Domain & Appropriation etc. is very important.
From an artist standpoint, it is wrong and illegal to take someone else’s work and claim it as your own for commercial use, unless the creator attributes the work for public domain or grants an individual certain rights / uses.
However, regarding recipes - like any other recipe you may find online there are laws regarding this on the U.S Copyright Office - Copyright | Recipes website.
I do highly suggest, that you should keep certain recipes private if you fear that vendors will use them for profit; without giving credit to you as the creator. Share what you wish to share and keep what you want to keep private. The best kept secret is one never told.
I’ve posted some information below if you are interested in reading.
Copyright law does not protect recipes that are mere listings of ingredients. Nor does it protect other mere listings of ingredients such as those found in formulas, compounds, or prescriptions. Copyright protection may, however, extend to substantial literary expression—a description, explanation, or illustration, for example—that accompanies a recipe or formula or to a combination of recipes, as in a cookbook.
Only original works of authorship are protected by copyright. “Original” means that an author produced a work by his or her own intellectual effort instead of copying it from an existing work.
For further information about copyright, see Circular 1, Copyright Basics. Note that if your recipe has secret ingredients that you do not want to reveal, you may not want to submit it for registration, because applications and deposit copies are public records.
Deposit requirements depend on whether a work has been published at the time of registration:
If the work is unpublished, one complete copy
If the work was first published in the United States on or after January 1, 1978, two complete copies of the best edition
If the work was first published outside the United States, one complete copy of the work as first published
If the work is a contribution to a collective work and was published after January 1, 1978, one complete copy of the best edition of the collective work or a photocopy of the contribution itself as it was published in the collective work
Public domain & Creative Commons
When a work is in the public domain, it is free for use by anyone for any purpose without restriction under copyright law. Public domain is the purest form of open/free, since no one owns or controls the material in any way.
Works that are in the public domain in one legal jurisdiction are not necessarily in the public domain worldwide. Copyright laws differ from jurisdiction to jurisdiction, both in duration of protection and what constitutes copyrightable subject matter. For example a US Government work clearly in the public domain in the United States may or may not be free of copyright restrictions and in the public domain in other jurisdiction. At present, one of the only ways to be certain that a particular work is in the public domain worldwide is to see if the copyright holder has dedicated all rights to the work to the public domain by using CC0.
Creative Commons licenses do not affect the status of a work that is in the public domain under applicable law, because our licenses only apply to works that are protected by copyright. For more information, see our Licensing Guide to what you should know before you license a work using CC licenses.
Find out more about CC’s public domain tools, and learn more about Public Domain.