I suddenly thought of something. Sorry if this is elementary — I don't have much experience with preservatives or understanding the mechanics of how they work.
You know how some preservative systems only effectively prevent/kill gram-negative bacteria (I presume from interfering with their lipid membranes)?
Gram-positive bacteria do not have lipid membranes; instead, they have thick peptidoglycan walls. Ideally, the gram-negative preservative system would not kill gram-positive bacteria.
The thing is, I read that gram-positive bacteria are typically "good" cosmeceutically-speaking. They benefit the gut when ingested (probiotics), but of course we don't have much research on topical uses. Let us assume that gram-positive bacteria are "good", even if we are fooling ourselves.
If I use a preservative system for gram-negative bacteria, will that not compromise the skin microbiome? There has been a worry about phenoxyethanol/other conventional preservatives damaging the bacteria on our skin. Antimicrobial peptide seem to target gram-negative bacteria, but that's not certain yet.
Will "bad" bacteria grow with only a gram-negative preservative system? I will combine it with other preservatives for fungi, yeast, and mold.
Thank you as always!