The answer is YES! Bacteria will grow on your soap if you use fresh squeezed juice when making it. The very best thing you can use is essential oils. They will not only be safe from bacteria they will give you aroma therapy while you bath. You can choose from a variety of oils and each oil has it's own benefit. Like lavender will relax you, while peppermint will give your spirits a lift. Essential oils aren't as expensive as they may seem since you only use a few drops to make your soap.