Preservative for Separated Formulation (Water and Oil Phases)
Question
If my formulation separates into water and oil phases, and the preservative I use, Nature Preserve, is water-soluble (meaning it stays in the water phase), do I need to add another preservative specifically for the oil phase? Or is Nature Preserve sufficient to protect the entire formula from microbial growth, even after separation?
Answer
Based on the information provided, Nature Preserve dissolves in water and will therefore be present in the water phase of your separated formulation. Microbial growth, which preservatives protect against, primarily occurs in the water phase. The oil phase generally does not require a preservative for microbial protection. Therefore, adding another preservative specifically for the oil phase is typically not necessary for microbial preservation. Note that oil rancidity (oxidation) is a different issue addressed by antioxidants, not preservatives.
