Comparison of preservative efficiency at different pH.

This data shows the MIC of a preservative blend at pH 5 and 7. It shows how much less preservative you need in pH 5 compared to pH 7 for bacteria. But it doesn't show this comparison for fungi. 

Can anyone tell that approximately how much will pH 4-5 increase the preservative efficiency compared to pH 7 for fungi.

Comments

  • PhilGeisPhilGeis Member, Professional formulator
    edited December 2021
    Do not presume you need less due to MIC.   You should use a generally effective level in each application.
  • @PhilGeis i am using the upper recommend level of preservative no matter what the pH is because i don't do PET test yet.

    I just wanted to know how much does preservative efficiency improve at pH 4-5 compared to pH 7 in an appropriate
  • PhilGeisPhilGeis Member, Professional formulator
    really need to establish PET
  • PhilGeis said:
    Do not presume you need less due to MIC.   You should use a generally effective level in each application.
    What do you think of that combo as a preservative?  I don't use that product...but I do use all three of those ingredients (plus others) in my formulas....(plus all the other hurdles).
  • About the combo, it is like this 
    1. 0.6% phenoxyethanol+0.25% caprylyl Glycol+0.15% hydroxyacetophenone.

    2. 0.7% phenoxyethanol+ 0.2% hydroxyacetophenone+0.1% caprylyl Glycol. 

    3. 0.5% phenoxyethanol+0.5% hydroxyacetophenone
  • PhilGeisPhilGeis Member, Professional formulator
    Think 0.5% phenoxy is enough.  The others are marginal - you need something better targeting fungi.
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