To Determine The IFRA Guidelines:
IFRA is a self-regulating trade organization that together with the industry's scientific center RIFM (the Research Institute for Fragrance Materials) establishes usage safety standards for materials that comprise fragrance and essential oils. Each year IFRA updates their standards based on sound science.
Flavor oils that contain vanilla or vanillin will change color. The color change can take days, weeks, or months and can vary from a light ivory to dark brown.