Preservative for rice powder product
I need help with a formula which is an anhydrous powder mainly based on Oryza sativa rice starch.
The main problem is the efficency of the preservative.
Despite it is anhydrous, the product is a shampoo powder and therefore water contamination can not be excluded and a preservative is reconmended due to the vegetal origin of the main ingredient. However, i could not be able to find a suitable preservative system capable to let the product pass the challenge test, expecially for fungi.
I tryed with both liquid and solid (which i finely crushed) preservatives but i am not sure if it is possible to homogeneously disperse them in the powder and more problematic, if the preservatives are in general active in powder products. Creams and gel based on rice are ok and they pass the challenge test easily and therefore is not a problem of “too much food” for fungi and bacteria.
So, this is the scenario. Some of you have any suggestion to how i can solve this? Any comment or experience would be extremely apreciated.
Thank you in advanded!