Generally can anyone direct me to safety and best practice in the use of essential oils as ingredients for beverages?
That is really much too broad a question to get a useful response. You might want to look into what you are thinking of doing in much more detail before you begin, to ensure that you do not compromise your health or safety, or anyone else's. In general, which is all that can be done with this question, visit the US-FDA site for free information on things like HACCP requirements. OSHA may have MSDS sheets for the specific oils (although they should be available from the manufacturers).
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