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Challenge test- “no increase” of mold
USP challenge test, for ex, calls for no increase of Aspergillus in 24 days (or something).
By “no increase,” hmmm, how strictly do they mean?
Do they mean no statistically significant increase? Or literally “equal to or less than” before?
I mean, if you plate out the same exact microbial sample at the same time in replicates, you get slightly different counts of bacteria/mold and that’s what I’m thinking about.
So say, if your initial count is 1.10 x10^6 CFU/mL and your final count after 24 days is 1.17 x 10^6 CFU/mL, just as an example, that can be an actual increase, OR, more likely, just plating error.
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9 Replies
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My approach would always be to have our QC Manager approach your cosmetics compliance authority and seek clarification.
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It is generally considered that +/- 0.5 logs is no change and this rule is included in USP <51> AET.
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I appeal to you - if your preservative system is so impotent it has no impact on mold inoculum - please please find a more effective system.
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100% agree with this comment. You don’t want to find a way to only just pass the test under controlled conditions. You want an effective preservative system that stops any growth from occurring.
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I plan to use potassium sorbate.
I was thinking ahead while waiting for Aspergillus to arrive for me to test. 🙂
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What are other preservatives and pH ?
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pH of 4-5 (TBD), and the other anti-bacterial parts, also TBD.
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Sir,i am new here.thanks a lot to join here me.
I have a question.
When i make shampoo and its pH is 5.0 to 5.50,but while i use it my hair fall down.?why please suggest me.
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<div>Hi Porag,</div><div>
The pH is one of many parameters that may be causing your hair to drop. May I suggest that you provide a list of ingredients for your shampoo formulation. This may provide a clue to your problem.
Kind regards,
Mike
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