Home Cosmetic Science Talk Formulating General Off Topic MIC and pH……

  • MIC and pH……

    Posted by Graillotion on October 1, 2023 at 11:26 pm

    I have to assume….in the context of preservatives….especially those that interact heavily with pH….that when MIC numbers are given…this is given in the context of a set pH.

    What is the pH assumption…that MIC numbers are given? Since I am working with Mummy bloggers….you can see where I am headed…. at what pH are those crappy preservatives presenting MIC data? I guess I also mean…when I look at scientific data…and they display MIC numbers….what pH was the reference point?

    Thank You in advance.

    @PhilGeis

    • This discussion was modified 6 months, 3 weeks ago by  Graillotion.
    PhilGeis replied 6 months, 3 weeks ago 2 Members · 7 Replies
  • 7 Replies
  • PhilGeis

    Member
    October 2, 2023 at 5:29 am

    Pretty sure MIC protocols all use media at +/- neutral pH. MIC is pretty meaningless - inhibition in an overnight culture is a pretty low modest target when the standard is stable kill through 4 weeks.

    • Graillotion

      Member
      October 2, 2023 at 2:01 pm

      @PhilGeis … so you are telling me….MIC numbers for organic acid based preservatives…are provided in an almost neutral environment….where they are essentially inactive?

    • Graillotion

      Member
      October 2, 2023 at 2:03 pm

      If MIC numbers have so little value…. What readily available information can one use, to make a proper evaluation?

      Again….I am not using these products….just trying to help those that have drunk the Kool-Aide.

      • PhilGeis

        Member
        October 2, 2023 at 2:31 pm

        It’s just inhibition (not kill) vs the wimpy lab strains and only for 12-24 hours..

        Efficacy in a formula - and experience wiith other formulas.

        • Graillotion

          Member
          October 3, 2023 at 2:43 pm

          So, in the land of poor preservatives that saturate the market….is it safe to say….the only marketing leg they stand on….is the MIC numbers…which in a nutshell….have very little applicable value?

          Aloha

          @PhilGeis

          BTW…. for the PET test/s you consider superior to

          • This reply was modified 6 months, 3 weeks ago by  Graillotion.
      • Graillotion

        Member
        October 3, 2023 at 2:47 pm

        Sorry…..some glitch cut me off……..

        …… Continued…….. For the PET test/s that you consider superior (more rigorous) than USP 51…. do they contain additional pathogens beyond the typical 5? A whole different slate….or a slate of the 5 plus some bonus contenders? I guess what I am asking…..what makes it more rigorous?

        • This reply was modified 6 months, 3 weeks ago by  Graillotion.
        • PhilGeis

          Member
          October 3, 2023 at 3:17 pm

          MIC - it’s pretty meaningless.

          For challemge - USP/EP/BP/ISO/ASTM all have the same bugs (these were 1st isolated 60 + years ago - the staph almost a century old) and are more of less identical but for acceptance criteria. ISO is ok but it offers the wriggle room of A amd B, and non of these demands the bugs actually be eliminated at any time point. In real life with real contaminants - bugs that hang around learn to grow.

          .Major companies that use this general challenge protocol demand even more - usually no detects at 7 days. They typically also add bugs that can or have contaminate esp, Burkholderia cepacia and a few others.

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