I just made some cucumber and green tea soap, Since I am fairly new at soap making.. for now I am using a preservative, 1% germaben.. I have not used any whole foods, usually extracts, oils and dried, though i did use fresh cucumber peel in my soap for the attractiveness of it in the sopa inself... you can use regualr old liquid food coloring in soap, its safe, you wont have a humongous broad range of color.. but it works great when you are just starting out an not wanting to invest a lot..i never had an mixing issues or weeping ,bleeding with it.