Currently preserving a hair gel product using a combination of Ethylhexyglycerin and PhenoxyEthanol. It seems to have a pretty good reputation as a preservative system, as it's broad based and can be used at up to 1%. I am going to invest in some dip-paddle type test kit so I can start to prove my preservative holds up before I attempt more expensive challenge testing by a lab. Noticed there are various test types:
1) Fungi, Yeast, Mold
2) Bacteria, non-fastiduous
3) Microorganisms (TSA) & yeasts and molds (RB)
4) Total coliform count (TCC) and non-lactose fermenting
My product would have fingers going in it every day to retrieve hair product and apply to the hair. It does not apply direct to skin, but I suppose some could get on the skin if one was not careful. My product is mainly distilled water, but is brought to near boiling temp along with some other emulsifying ingredients before packaging.
Would appreciate any input on the type of test I should use. My gut tells me the yeast, mould, fungi, as that is what my preservative is aimed at preventing.