***Update March 26, 2021.
I'm pleased to announce that after several weeks of testing, I have found a paraben-free preservative that keeps the Conditioner Bar safe for use. I am now using glycine-benzoic acid. In addition, this full spectrum preservative contains no components considered to be either persistent, bioaccumulative or toxic to the environment.
***end Update
In my online stores, I sell only one product that contains a preservative, the Moisturizing Cocoa Butter Conditioner Bar. The rest of my product line are cold process soaps which contain a high enough ph to prevent mold and bacteria growth.
The Conditioner Bar I make does not contain water, however since it's used in the shower and will get wet, I add a very small amount of Phenonip preservative (less than 1%.). The full ingredients for Phenonip are Phenoxyethanol, Methylparaben, Ethylparaben, Butylparaben, Propylparaben. IThere is much debate regarding parabens in skin and hair card products and I encourage you to do your own research, but regardless of where you land on the debate, the quantity at which they are used in my Conditioner Bar is so small that I feel comfortable in using them. What I don't feel comfortable about, and what would be more dangerous, is to sell a product to the public that could grow a microbe in it and possibly harm someone. My own opinion on them is I don't, nor would I encourage anyone to use multiple products that contain them everyday in large quantities. I also question new alternatives to parabens that have been proven to be more dangerous or at best, less well known.