You don't need to read very far before running into the ongoing back-and-forth debate about whether or not preservatives are needed in liquid soap, with very intelligent, science-credentialed people standing on different sides of the fence.
Although I use a preservative system in my lotion (Phenonip in conjunction with Tetrasodium EDTA), I don't use any in my liquid soap. I've read plenty on both sides of the debate, and since I don't sell, I have chosen to err on the side of using none.
I should mention, though, that I do use Tetrasodium EDTA in my liquid soap (to combat hard water issues). Although it's not a preservative, by the way, and it won't actively kill bacteria/molds/fungi, I thought I'd mention it because it does happen to help in somewhat of a more clandestine way by starving those things of their food so that's it's more difficult for them to multiply.
Here's a discussion that helped me greatly in making my decision to forego using a preservative in my liquid soap (start at post #997 by SilverDoctor):
http://www.thedishforum.com/forum/i...7-glycerin-method-liquid-soap/page-40?hl=edta
Again- I want to mention that I don't sell. If I did, though, I would use one because it's a good thing to have all your bases covered just in case, and I would use Liquid Germall Plus since it works in all levels of pH. Several preservatives don't, by the way, so you have to be mindful of that.
Also, some preservatives are rendered ineffective by certain ingredients such as polysorbates, etc.., so if you use those in your formula to help emulsify superfats or FOs in your liquid soap (as I do), you need to be mindful of that, too.
IrishLass
