Microbial/Preservative testing in cosmetics

Tagged: microbial-testing, preservatives

General

Microbial/Preservative testing in cosmetics

Posted by Herbnerd on May 26, 2022 at 12:18 am

I haven’t been able to find the answer, it may be I’m looking in the wrong place or incorrect search terms.

When conducting preservative efficacy tests, is there a particular standard you follow?

For some historical reason we have been using the British Pharmacopoeia PET test protocols - but since we are manufacturing cosmetic do we need to conduct PET to a specific pharmacopoeia (ie BP or USP)?

Bill_Toge replied 3 years, 1 month ago 4 Members · 12 Replies
- microbial-testing
- preservatives
12 Replies

PhilGeis

Member
May 26, 2022 at 11:02 am

Suggest at minimum you use CTFA method. In any case, preserve for complete elimination in 7 days or less, not the %’s.
Abdullah

Entrepreneur
May 26, 2022 at 3:23 pm

@PhilGeis complete elimination of yeast & mold too in 7 days?
PhilGeis

Member
May 26, 2022 at 3:23 pm

Yes - but I’d not bother with mold for surfactant products.
Herbnerd

Member
May 26, 2022 at 6:09 pm

@PhilGeis Thanks for that. We seem to be getting bogged down (mostly by a micromanaging manager) who is insisting we compare BP, EP, USP, ISO/TR 19838 etc.

I’ll see if I can get hold of a copy.
Abdullah

Entrepreneur
May 27, 2022 at 12:03 am

@PhilGeis is it so only in surfactant products with high amount of anionic surfactant or any surfactant product?

For example when a product has

2% SLS
2% SLES
1% CAPB
1% APG
Total 6% active surfactant with 4% being anionic.
PhilGeis

Member
May 27, 2022 at 10:20 am

I’d test that one as prototype.
Abdullah

Entrepreneur
May 27, 2022 at 12:26 pm

PhilGeis said:

I’d test that one as prototype.

Got it
Thanks

If this is the ratio, what percentage of total surfactants should be in system so that you would not bother with mold for surfactant products as a general rule?
PhilGeis

Member
May 27, 2022 at 5:37 pm

%
Abdullah

Entrepreneur
May 28, 2022 at 1:04 am

PhilGeis said:

%

Currently i am using
185ppm formaldehyde as (formalin)

0.45ppm CMI MI

0.1%EDTA

pH 5.1 in cleansing products.

My question was if the ratio of surfactants is 4/1/1 anionic/amphoteric/non-ionic, if total surfactant is 6%, we need to test for mold too. At what percentage of total surfactant at this ratio we don’t need to bother with mold?

Package is flip top cap.
PhilGeis

Member
May 28, 2022 at 11:31 am

I’ve no specified number. My experience has been in shampoos and hand wash.
Abdullah

Entrepreneur
May 28, 2022 at 3:18 pm

PhilGeis said:

I’ve no specified number. My experience has been in shampoos and hand wash.

This is also a Shampoo formula. Low surfactant and inexpensive.
Bill_Toge

Professional Chemist / Formulator
May 28, 2022 at 9:55 pm

ISO 11930 is the most rigorous method that’s generally recognised