Preservatives screening

I want to ask about how you guys screen your preservatives—type and level, but especially level.
I assume people don’t use the highest recommended concentration for a preservative…or do you?
That being said, do you have any practical procedure you regularly follow to determine the minimum preservative concentration without having to send multiple samples for challenge tests?
Thank you

Comments

  • BelassiBelassi Member, PCF student
    I can only speak for myself. Fortunately it was early days. A customer came back with a hand cream infested with A. Niger. The whole batch went that way. After that kind of experience you tend to use the maximum permitted level or at least the manufacturer's recommended level.
    Cosmetic Brand Creation. Concept to name to IMPI search to logo and brand registration. In-house graphic design inc. Pantone specs. Cosmetic label and box design & graphics.
  • MarkBroussardMarkBroussard Member, Professional Chemist
    Second Belassi's comments.

    First, make sure the preservative(s) you use don't have any incompatibilities with any ingredients in your formulation or with the packaging you intend to use.  And, make sure you have a preservative combination that gives you broad spectrum coverage.  I generally combine two different preservative blends.  For instance, Gluconolactone/Sodium Benzoate with Benzyl Alcohol/Dehydroacetic Acid.

    Second, make a batch at the High (maximum permitted level) and mid-range of the manufacturer's recommended level to bracket your concentrations.

    Test your batches with Schuelke & Mayr Mikrocount Combi test strips.  If you get a pass with the test strips, then it's off to the lab for Preservative Challenge Test.
    Chemist/Microbiologist formulating in the Organic & Naturals arena under ECOCert/Natural Products Assn/Whole Foods/National Organic Program guidelines focused skincare & haircare products. 

    See website for details www.desertinbloomcosmeticslab.com
  • RubenRuben Member
    edited February 2015
    How reliable are these test strips? Doesn't the preservative inhibit the growth of microorganisms on the strips?
  • PerryPerry Administrator, Professional Chemist
    And for preservative challenge tests this is a reliable company.  Cosmetic Test Labs

    @The_Microbiologist runs the company.  Also, you should see this discussion about microbial questions if you haven't.

    I also agree.  Use the maximum level as suggested by the raw material manufacturer if you can.
  • MarkBroussardMarkBroussard Member, Professional Chemist
    @Ruben:

    The test strips are quite reliable.  One side supports the growth of bacteria and the other yeasts/mold using different types of agar.

    Yes, the preservative inhibits the growth of microorganisms on the strips ... that's the whole idea.  If your preservative is working, you won't get any growth at all.
    Chemist/Microbiologist formulating in the Organic & Naturals arena under ECOCert/Natural Products Assn/Whole Foods/National Organic Program guidelines focused skincare & haircare products. 

    See website for details www.desertinbloomcosmeticslab.com
  • BelassiBelassi Member, PCF student
    Where on earth do you get those test strips? I searched on Google with no results, tried EBay, nothing.
    Cosmetic Brand Creation. Concept to name to IMPI search to logo and brand registration. In-house graphic design inc. Pantone specs. Cosmetic label and box design & graphics.
  • MarkBroussardMarkBroussard Member, Professional Chemist
    @Belassi:

    Here you go:


    I'm sure there is a Schuelke distributor covering Mexico.  If you can't find one, let me know and I'll give you a couple of contacts.
    Chemist/Microbiologist formulating in the Organic & Naturals arena under ECOCert/Natural Products Assn/Whole Foods/National Organic Program guidelines focused skincare & haircare products. 

    See website for details www.desertinbloomcosmeticslab.com
  • MarkBroussardMarkBroussard Member, Professional Chemist
    @Belassi & @Ruben:

    If you buy them direct from Schuelke, they're about half the price.  Plus, if you use any Schuelke Preservative or Preservative Booster in your formulation, Schuelke will perform a 6-week KOKO challenge test on any samples you send them for free, you only need pay the shipping to their labs in Germany.


    Chemist/Microbiologist formulating in the Organic & Naturals arena under ECOCert/Natural Products Assn/Whole Foods/National Organic Program guidelines focused skincare & haircare products. 

    See website for details www.desertinbloomcosmeticslab.com
  • MarkBroussardMarkBroussard Member, Professional Chemist
    @Ruben:

    If you have any doubts about the reliability of the test strips, dip your finger into an unpreserved sample and into a preserved sample; also test a preserved sample into which you have not dipped your finger.  Run the 3 test strips side by side.  You'll get growth on the finger-dipped, unpreserved sample.  If your preservative is working, you should not see any growth on the two preserved samples.  
    Chemist/Microbiologist formulating in the Organic & Naturals arena under ECOCert/Natural Products Assn/Whole Foods/National Organic Program guidelines focused skincare & haircare products. 

    See website for details www.desertinbloomcosmeticslab.com
  • My point of minimizing the level of preservative is to reduce the risk of adverse skin reactions.
    Especially when using airless bottles--which it seems to help to prevent product contamination-- I though there was no need to go full blast with the preservative. But it seems the consensus is to use the maximum level suggested by the manufacturer

  • MarkBroussardMarkBroussard Member, Professional Chemist
    In that case, stay away from Potassium Sorbate which can cause a flushing reaction in some people.  It's the only preservative that I've ever had a reaction to.

    What preservatives are you considering using?
    Chemist/Microbiologist formulating in the Organic & Naturals arena under ECOCert/Natural Products Assn/Whole Foods/National Organic Program guidelines focused skincare & haircare products. 

    See website for details www.desertinbloomcosmeticslab.com
  • BelassiBelassi Member, PCF student
    The problem, Ruben, is that ONE failure will affect the entire batch and potentially result in your losing the business when words get out. We live in a world of social media. Can you imagine if one of your customers posts an image on social media of one of your products full of colourful fungus?
    Cosmetic Brand Creation. Concept to name to IMPI search to logo and brand registration. In-house graphic design inc. Pantone specs. Cosmetic label and box design & graphics.
  • @MarkBroussard

    I use mainly Optiphen Plus for creams, lotions, and gels.




  • MarkBroussardMarkBroussard Member, Professional Chemist
    With Optiphen Plus you really should not have to worry about adverse skin reactions even though it contains Sorbic Acid.  I use it a maximum concentration and have never had an issue.
    Chemist/Microbiologist formulating in the Organic & Naturals arena under ECOCert/Natural Products Assn/Whole Foods/National Organic Program guidelines focused skincare & haircare products. 

    See website for details www.desertinbloomcosmeticslab.com
  • BelassiBelassi Member, PCF student
    Thanks Mark. I found the rep in Mexico and have left a query for them.
    Cosmetic Brand Creation. Concept to name to IMPI search to logo and brand registration. In-house graphic design inc. Pantone specs. Cosmetic label and box design & graphics.
  • PerryPerry Administrator, Professional Chemist
    I was just shaming a company today on social media due to selling contaminated products.

    "Congratulations on producing dangerous, microbial contaminated products @gilchristsoames How about using a proper preservative next time?"

    That was in reference to a recent product recall they experienced due to microbial contamination.

  • Thank you! Your answers really help

    Since we are discussing preservatives, I have another question.

    Liquid Germall Plus seems to be a very robust preservative and broadly used by hobbyist. However, I haven't seen it in many commercial products. Actually I just saw one commercial gel preserved with Liquid Germall Plus.
    I wonder if there is a reason for cosmetic companies not to use this preservative.
  • PerryPerry Administrator, Professional Chemist
    Probably because you can get other things that work as well for less money if you're a big company.  Although I remember Germall Plus being one of the ingredients companies tried to sell us.  There was just no reason to use it since it was more expensive than DMDM Hydantoin & not more effective.

    Incidentally, Germal Plus uses a formaldehyde donor (diazolidinyl urea) for it's functionality.
  • BobzchemistBobzchemist Member, PCF student
    As Perry and Belassi pointed out, the downsides of selling a contaminated product are far, far greater than the downsides of selling a product with too much preservative.

    The FDA could fine you and/or force a recall. They could shut down your company. Worst case, you could go to jail.

    Compare the costs of that to the costs of a few adverse reactions. Which wins? 
    Robert Zonis, Sr. Formulation Chemist, Beaumont Products "All opinions and comments expressed are my own, have no relation to Beaumont Products, are fully copyrighted, and may not be used without written permission."
  • heraklitheraklit Member, PCF student
    I combine Geogard 221 with Euxyl 9010 for my home shampoo - 0.4% each.
  • RubenRuben Member
    I just realized I didn't say thank you. So, thank you for your comments. They will definitely help
  • RubenRuben Member
    Interestingly, C&T published an article this month about preservatives that mentions something related to the initial concern I had when I stated this thread.

    If you scroll down, under the title "Safe Preservation" the author talks about a "balancing act" between "preventing microbial growth" and avoiding problems to human skin.
  • @Ruben

    Great topic! I was actually wondering the ratio myself just the other. I always err on the side of caution out of pure fear and "big go or go home" when it comes to preserving. I'd hate to get anyone sick or worse. I typically use Germaben or Germall Plus (I alternate per formula), though I do have Paraben DU (bought after a comment @Perry made ;)) ) and Optiphen that I use.
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