This wiki page https://en.wikipedia.org/wiki/Essential_oil says that "In relation with their food applications, although these oils have been used throughout history as food preservatives, it was in the 20th century when EOs were considered as Generally Recognized as Safe (GRAS) by the Food and Drug Administration (FDA)."
And ... there is a long list of essential oils on the page under the title of "Use in food" ...
Do you use essential oils in your ganaches safely?
Bitter almond, peppermint, thyme, orange, lemon, etc ...