• Formulating

  preservative when is it needed

  Posted by Stanley on August 6, 2021 at 8:04 pm

  This is a 2 part question…
  If the pH of my water based system (73.0% h20) is below 4.00 does it need a preservative?  I am trying to  find a preservative that will allow my system to stay clear under pH 4.00

  mikethair replied 3 years, 3 months ago 3 Members · 2 Replies
• 2 Replies

• 

  PhilGeis

  Member

  August 6, 2021 at 8:39 pm

  It does - pH 4 is not prohibitive.

• 

  mikethair

  Member

  August 7, 2021 at 12:31 am

  I usually refer to ISO 29621 -

  Cosmetics — Microbiology —
  Guidelines for the risk assessment
  and identification of microbiologically
  low-risk products

  In certain product types, where extreme pH levels are reported, those considered pH ≤3,0 and pH ≥10,0
  do not require microbiological testing, including both challenge-test and end-product testing. At all
  other pH values (>3,0 but <10,0), a combination of pH and other Physico-chemical factors needs to be
  evaluated to determine potential risk.

Log In to Reply